Add option to disable username changing

Ssh fingerprint fix

Fix link to owner of group and team in admin interface

Fix gitlab:setup task on fresh installation

Fix file_name for archive

fixed API access to the project

Remove hardcoded refernce to gitlab-shell home. so that gitlab can be installed on any unix account other than git

OS X support for gitlab:check rake tasks

This option allows to disable users from changing their username.

This is very usefull in environments using strong internal authentication methods like ldap, pam or shibboleth.

You can allow users to change theyr username in these environments, but then new users (users loging in first time) is blocked from gitlab is her username exists.

Environments support added to Gitlab config

archive download : namespace directory not created