Installation was working fine because Skin Folder are not ERP5 object but when
updating the bt5, it failed because Folder objects are saved as Trash Folder
(ERP5 object).

Signed-off-by: Jérome Perrin <jerome@nexedi.com>

Also, add Javascript and CSS linters.

erp5_code_mirror: Gutter and source code separator line was not displayed because of erp5.css (df7eb0fd).

Incompatibilities fixed:
  * python-hint.js was removed in favor of hintWords functionality (TODO for ERP5).
  * diff_match_patch is not shipped with CodeMirror anymore.
  * lint addon API change.

This will display warnings/errors icons next to the line number, likewise Ace
Editor implementation.

erp5_code_mirror: Refresh Component history revisions (used for merge mode) when saving with CTRL+s.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@42291 20353a03-c40f-0410-a6d1-a30d3c3de9de