Revert and re-fix image rendering in help pages

Closes #2212

See merge request !1765

Changes for 7.10.0.rc4

cc @job @douwe

See merge request !1785

Revert disallowing usernames to end in period.

cc @JobV @jacobvosmaer

See merge request !545

Remove access control for uploaded images to fix broken images in emails

Replaces !530.

> This MR removes the access control for uploaded images. This is needed to display the images in emails again.
>
> The previous solution to base64 encode the images had to be reverted, because not all email clients supported it.
>
> If possible this should go into the 7.10 release.

See merge request !533

Parse GFM references after sanitizing

Parse GFM references - labels, issues, MRs, etc. - after calling the HTML Pipeline `SanitizationFilter` so that we can use non-whitelisted attributes like `style`.  See #2188.

See merge request !1745

Fix label color input.

Because `value` was set, every label color would render as purple in the form.

Introduced by 83b5a9ae between 7.9 and 7.10, so no changelog item.

See merge request !538

Fixes for 7.10.0.rc3

content

- [ ] Update gitlab_git to ignore invalid lines in .gitmodules.
- [ ] Add a task that checks repository integrity with `git fsck`.
- [ ] Decrease memory use and increase performance of Google Code importer.
- [ ] Fix username period migration to preserve uniqueness of names and paths.

See merge request !1783

Decrease memory use and increase performance of Google Code importer.

Addresses private issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2241.

See merge request !536

Add a task that checks repository integrity with `git fsck`.

ruby 2.1.6

update text to reference new location of setting

update guides for 7.10

See merge request !1779

Fix merge request comments on files with multiple commits

Fix Mention notification level.

Fixes internal issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2236.

See merge request !527

Having a merge request with a comments on a line which is then changed
in a later commit prevented new comments from properly showing up in the
merge request show page.

 * `Note#set_diff` do not use stored the diff when creating a new note
   in merge requests (we can not be sure the diff did not changed since
   the last comment on that line)
 * Do not rely just on `outdated?` of the first note when displaying
   comments of a MR in the discussion tab, but partition the
   active/outdated notes and display them all
 * In the inline changes tab just select the active notes, so an
   outdated note does not prevent an active one from being rendered
 * Just show active comments in the side-by-side changes tab

Make sure user has access to namespace in import tests.

See merge request !529

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fix generating SSH key fingerprints with OpenSSH 6.8.

Replaces https://github.com/gitlabhq/gitlabhq/pull/9008.

Fixes gitlab-org/gitlab-ce#1289.

cc @jacobvosmaer

See merge request !519

Set EmailsOnPush reply-to address to committer email when enabled.

Addresses private issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2227.

See merge request !520

Don't use HTML ellipsis in EmailsOnPush subject truncated commit message.

Addresses private issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2229.

Since the page is encoded as UTF-8, we don't need HTML entities anymore and can just use the character.

See merge request !521

Add config var to block auto-created LDAP users.

Addresses private issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2110.

See merge request !522

Don't crash when project repository doesn't exist.

See merge request !524

Don't leak existence of group or project via search.

Fixes gitlab/gitlab-ee#266.

See merge request !1762

Update gemnasium-gitlab-service to 0.2.6

Allow users to be invited.

Addresses private issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2058.

The "Add members" panes for both Group Members and Project Members have gained a line of text by the People field.

![Screen_Shot_2015-04-10_at_14.14.32](https://gitlab.com/gitlab-org/gitlab-ce/uploads/fe990e65eccd9203d7324b492941362b/Screen_Shot_2015-04-10_at_14.14.32.png)

Entering an email address that is not already a member will give you the option to invite them.

![Screen_Shot_2015-04-10_at_14.14.48](https://gitlab.com/gitlab-org/gitlab-ce/uploads/d6b0d4571ea90f2a2e4af8f5b336e8e1/Screen_Shot_2015-04-10_at_14.14.48.png)

Choosing the option will add them to the People field. This works the right way (TM) in combination with adding existing users as members.

![Screen_Shot_2015-04-10_at_14.15.09](https://gitlab.com/gitlab-org/gitlab-ce/uploads/a618e5ec292d79578b16400dca6d4cfe/Screen_Shot_2015-04-10_at_14.15.09.png)

The invited member will be shown in the members list as such. The access level can be changed, and the invite can be revoked by deleting the member.

![Screen_Shot_2015-04-10_at_14.15.19](https://gitlab.com/gitlab-org/gitlab-ce/uploads/3695b9a6778d367b275115747579b46e/Screen_Shot_2015-04-10_at_14.15.19.png)

The invited user will receive an email with an "Accept invitation" link.

![Screen_Shot_2015-04-10_at_14.17.52](https://gitlab.com/gitlab-org/gitlab-ce/uploads/730121888153117d83c3cd0e4f5c90f6/Screen_Shot_2015-04-10_at_14.17.52.png)

If they're not already logged in, clicking this link will redirect them to the sign in/up page with a helpful notice.

![Screen_Shot_2015-04-10_at_14.18.12](https://gitlab.com/gitlab-org/gitlab-ce/uploads/1a26a5fa13321e7ef77ed8b538c8557d/Screen_Shot_2015-04-10_at_14.18.12.png)

Signing in or signing up will redirect them back to the invite detail page, where they can actually accept the invitation, which will update the member record in question to point to the user in question.

![Screen_Shot_2015-04-10_at_14.18.48](https://gitlab.com/gitlab-org/gitlab-ce/uploads/7ac33085463a99b8cfa6baa13bfa1235/Screen_Shot_2015-04-10_at_14.18.48.png)

Accepting the invitation will redirect them to the group (or project) with an appropriate notice.

![Screen_Shot_2015-04-10_at_14.18.58](https://gitlab.com/gitlab-org/gitlab-ce/uploads/7bf02a2e3bea589a11df401c23e68648/Screen_Shot_2015-04-10_at_14.18.58.png)

As currently, they will also receive this information by email.

![Screen_Shot_2015-04-10_at_14.24.00](https://gitlab.com/gitlab-org/gitlab-ce/uploads/b44a342068433a268c0a06ed9e791ffa/Screen_Shot_2015-04-10_at_14.24.00.png)

At the same time, the person who initially invited the email address is sent a notification as well, so they know of the new member and to tell them what name the user signed up with.

![Screen_Shot_2015-04-10_at_14.19.07](https://gitlab.com/gitlab-org/gitlab-ce/uploads/b29fea128186f938ec76bd7dec016b83/Screen_Shot_2015-04-10_at_14.19.07.png)

The member row on the Members page will now have been updated with the new user account.

![Screen_Shot_2015-04-10_at_14.19.23](https://gitlab.com/gitlab-org/gitlab-ce/uploads/cf503d3d1679614e03acec2e946a28c3/Screen_Shot_2015-04-10_at_14.19.23.png)

See merge request !500