Added project has_one :last_event assoc. Fixed tab line-height after font-awesome. Increased projects per page on dashboard

http://guides.rubyonrails.org/security.html#regular-expressions

default_branch now defaults to nil, not 'master'. It will be set after the first
push by discover_default_branch.

Merge branch 'master' into non-interactive-aws-install

Conflicts:
	doc/installation.md

Fix merge mess in installation.md

Didn't bother with files in db/, config/, or features/