update previous tree item after switching repos
show active branch in tooltip of RepoTree
added invalidate method to RepoInfoModel
use invalidate method of model instead of a direct dataChanged() call
removed invalidation calls to the repo model from the repo tree view
registered repo model invalidate as a slot
connect the invalidate slots on (de-)activation of repo items
renamed invalidate -> invalidateRepository
removed spaces in SIGNAL() SLOT() makros
Merge pull request #66 from macgitver/topic/RepoTree

Improvements to repository tree