Hide admin menu for non-admins

Conflicts:
	app/models/project.rb
	config/routes.rb
	db/schema.rb

Alert only commit author on note

Added missing link to favicon

Allows to alert only the commit author when a new note is added on a commit, useful when gitlabhq is used for code
reviews, allows less noise with mails...

Solved issue #188

Fixes Timeout When Adding an SSH key with Many Projects 

Users with many projects (>100) will hit the 20 second timeout when
updating the gitolite config. This fix batches those changes into a
signle update to the file, causing an order of magnitude speed increase
which finishes well below the 20 second timeout.

Fixes gitlabhq/gitlabhq#220

This reverts commit f80745b7.

Project destroy relationship speed fix