Fix Markdown help page

see http://about.travis-ci.org/blog/august-2012-upcoming-ci-environment-updates

This reverts commit 6471d8c6.

Was "User has already been taken", is now "User already exists in
project".

refactor factory specs

Merge branch 'normalize_capitalization' of https://github.com/AlexDenisov/gitlabhq into AlexDenisov-normalize_capitalization

Refactoring

validate boolean attributes

Default branch auto-discovery

Unused routes removed

That was the only place it was used.

As a last resort it was calling a method that didn't exist. Woops!

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