Version fixes

Here are some changes to improve handling of Kubernetes versioning.
1) Now all commands are able to parse a -version flag.
2) Version generation from git is more robust and more complete.

Hm... I like seeing the "AndExit" part, but that makes it ungainly...

PrintAndExitIfRequested?
ShowAndExitIfRequested?
ShowAndExitIfFlag?

Maybe just too much info for one name. I guess the other possibility is to give no info:

Init?
HandleFlag?
CheckFlag?