Puppet 2.7.3 support plus Exported Resources

Hey there,

Modified the syntax validation to use Puppet 2.7.3's "puppet parser validate" command, with support for validating use of Exported Resources. Also tweaked the UI to load in a tooltip, and to output the version of Puppet being used to run the syntax check.

I couldn't get this to work with RVM unfortunately, so you need to have Puppet in your system gem path, along with the ActiveRecord gem (but no DB required), so that the Stored Config validation works.

Thanks!
Ryan