added puppetlabs_spec_helper to Gemfile
added puppetlabs_spec_helper/rake_tasks to Rakefile
added .fixtures.yml, puts vcsrepo into place for testing
updated tests for vcsrepo

Tests on git execs are now testing the vcsrepo declarations. The test
covering plugin updates has been removed since ensure => latest on
vcsrepo should cover that.

Also fixed some errors caught by testing... yay tests!