Merge branch 'use_gollum_wikis' of https://github.com/DanKnox/gitlabhq into DanKnox-use_gollum_wikis

Conflicts:
	app/views/layouts/project_resource.html.haml
	app/views/wikis/edit.html.haml
	app/views/wikis/pages.html.haml
	app/views/wikis/show.html.haml
	spec/features/gitlab_flavored_markdown_spec.rb

This commit enables the usage of the Gitlab Markdown post processing
on all Markdown formatted files. For file types that do not contain
Markdown, it defaults to the Gollum native renderer to process the
content.