Refactoring tests to not call private methods...

The mocks do seem a little busy, should probably fix this later...
Awesome way of checking Vagrant version!

Totally stolen from @tmatilai in his excellent https://github.com/tmatilai/vagrant-proxyconf code :+1:
Adding plugin spec file

Tests the newly added Vagrant version checks :+1:
Removing old plugin spec
Adding validation for provision_url
Moving require_relative for plugin spec
Adding plugin_spec
Adding config specs for validating provision_url
Adding helper method to spec_helper
Fixes so simplecov and coveralls both work
Half this setup isn't needed...

I still really need to refactor this, still not super sure how to mock half these things...
Dont need .rspec

Closes #2