Use poltergeist instaead of capybara-webkit

Also fixes #1983

Remove backward compatibility of factories.

Ensure git can commit and prevent it from failing silently

Update thin closes #1765 and maybe #1051

Conflicts:
	doc/install/installation.md

Update app/views/notify/project_access_granted_email.html.haml

changing wording to sound more better.  

release a new version of grit_ext, added it into Gitlab.

Add pointer about alternative platforms

Turns out git commit returns with 128 when user.name config not present.

Also updated status task and installation instuctions.