Handling of bare repositories

[mbonaker]

[mbonaker]

'git init --bare' is implemented since c5acb97

[mbonaker]

Bare repositories are recognized as repositories since d646da9
But behavior is still buggy as only 'git fetch', 'git push' and 'git remote' work but the other operations are also offered.
#20 should add a possibility to make use of the other buttons (except 'git commit').