api: gracefully handle errors on repos that are damaged or missing from filesystem.

authn: Data migration for renaming 'container' to 'headers'. Rename the 'auth_plugins' setting and all 'auth_container_%s' settings.

authn: Renamed auth_container -> auth_headers

login: Fix login redirection when came_from not set.

login: Moved method out of login view.

setup: Remove DB setting entry from rhodecode setup code.

authn: Add whitespace stripping to authentication plugin settings.

colander: Add a colander preparer to remove trailing/leading whitespace.

authn: Add container authentication plugin again.

authn: Add an INI option to set an authentication plugin fallback. #3953 If you set 'rhodecode.auth_plugin_fallback = egg:rhodecode-enterprise-ce#rhodecode' in your INI file the rhodecode auth plugin is always appended to the list of plugins that are used for authentication.