Fixed infinite loop when root folder is not a git repository

Looks like you just missed the "did I reach the root directory without finding anything" checks in a couple places.  So, I just copied the code from the place that had it to the two that were missing it.  This seems to fix the issue.
Changed VagrantBaseCommand to be a WindowCommand instead of an ApplicationCommand
Removed getVagrantConfigPath from VagrantInit and VagrantBaseCommand
Changed VagrantBaseCommand is_enabled to use getVagrantConfigPath from Vagrant instead of self.
Full Disclosure: I'm not that great of a python programmer, so this last part is probably non-idiomatic.  But it's working for me.
Merge pull request #6 from adamjgray/master

Updated Fix for #2 - Command palette hang while searching for Vagrantfile