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
Merge pull request #67 from macgitver/feature/ReferenceView

Corrected Git::Reference comparison to highlight references pointing to head commit
The input repository can no longer be NULL

so don't check for it.
No need to check active repositroy on booting

We will receive an event after being created.
Port RepoTree to split activation events
Use new signal from RepoManager for close action
Port IndexWidget to Deactivation-Signaling
Add missing include
removed spaces in SIGNAL() SLOT() makros
Merge pull request #66 from macgitver/topic/RepoTree

Improvements to repository tree
Merge pull request #68 from macgitver/topic/ImprovedRepoMan

Topic/improved repo man
Remove slot declaration
Fix value of RepoInfoModel::IsActive