feature to quickly add current user to the reviewers list.

This change adds an 'add me' button to allow the currently logged in user
to quickly add herself to the reviewers list.

Change-Id: I065634970d6afab00659b16cbf14e97c313640ea
feature: issue 2573
Fix caching of configs in ProjectState

ProjectState is caching project config files, but it only used the
file name as key and not the ref, which is an issue if the same config
file appears in different refs. This is e.g. the case for the
preference.config file in which the user preferences are stored as it
exists in each user ref. As result most users were getting the wrong
preferences for the 'My' menu entries.

Change-Id: Ib557ff3520bae1a8ee40e3ba6f1b3a8fdd3f880a
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>