Change of Modulefile name to match required format for puppet module install to work correctly.

Additional info on the spec can be found at: http://docs.puppetlabs.com/puppet/2.7/reference/modules_publishing.html#a-note-on-module-names
Added a note about upgrading with puppet module to resolve the package name bug.
Merge pull request #22 from OddEssay/master

Update the package name, and added a comment in the README to fix #18