Mode User+LDAP functionality from Gitlab::Auth
Move ldap auth to LDAP::User. Removed unused code
Remove include of grack_ldap
Dont show remove user button for ldap user
Added Gitlab::OAuth::User class

Authenticate or create users from OAuth providers
Inherit Gitlab::LDAP::User from Gitlab::OAuth::User
Use new OAuth classes
Refactor Gitlab::Auth
Improve Profile#account page
Rewrite OAuth specs
Fix user remove tests. Remove user even if he has projects
Merge branch 'refactor/oauth' of /home/git/repositories/gitlab/gitlabhq
Merge branch 'master' of github.com:gitlabhq/gitlabhq