Add autorequire for Package['git']

If the git package is being managed, it stands to reason that the git
package should be installed before trying to potentially manage git
repositories using vcsrepo resources.

This commit adds an autorequire to the vcsrepo type that reflects the
above premise.
Merge pull request #98 from reidmv/autorequire_git

Add autorequire for Package['git']
Prepare 0.2.0 release.
Merge pull request #102 from apenney/020-release

Prepare 0.2.0 release.