Read-only email field for LDAP user

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix default branch being cached and show old one after change

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Improve preview/edit links for comment form

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Rollback preview button href

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Minor UI improvements

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'feature/readonly_ldap_email' of /home/git/repositories/gitlab/gitlabhq
Merge branch 'bug/default_branch_cached' of /home/git/repositories/gitlab/gitlabhq
Merge branch 'improve/preview_button' of /home/git/repositories/gitlab/gitlabhq