Remove new action on repository_directories.
Ajaxify directory creation

The 'Create subdirectory' button now adds a line to the file browser
containing a form. When this form is sent, an XHR is sent. If the
directory could be created, the form is replaced by a link. Otherwise
an error message is shown.

The user can show as many forms as he wants.
Hound strikes again.
Remove dead code on last commit of a file

This was originally bringit code that showed information on the last
commit of each file in the file browser.

This was deactivated (but not entirely deleted) because of serious
performance issues on big repositories.
Allow to create a directory in an empty repo.
Merge branch '961-folder_creation' into develop

Conflicts:
	app/assets/javascripts/repository_directories.js.coffee
	app/views/files/_show_dir.html.haml