Rename: unicorn.rb.orig --> unicorn.rb.example

Updated development docs

Renamed unicorn.rb.orig to unicorn.rb.example since this seems to be more in line with the common used naming in the config directory. Plus seeing *.orig files I think of the leftovers of git merges, which left me puzzled for quite some time.

Merge branch 'change-notes-order' of https://github.com/riyad/gitlabhq into riyad-change-notes-order

Repaired Get patch

Fix HTML entities being parsed in GFM

Also fixes the spec so that it actually tests the thing it says it's
testing. Hooray!

Closes #1308

Be more resilient in the case of missing omniauth settings

Should no longer freak out when omniauth settings aren't present in
gitlab.yml. People who aren't using it shouldn't even have to put a
'false' entry in their config for it (and probably wouldn't, after an
upgrade).