Debian patchset against 0.4.9 release

[spog]

Commits of this pull request represent the state of debian patches needed for the 0.4.9 upstream release. There is actually another patch, which fixes the broken test 'push-after-init' in 0.4.9, but that had already been fixed upstream after 0.4.9 (b00d41b, 57de7d6).

There is still an open question about howto address Windows compatibility in some of the patches.
Anyway, here is the summary of what we want to achieve:

• fixing bash-completion integration with git
• running tests in predictable git environment
• generating test git repos instead of commited binaries