COOK-2505 - backport Omnibus builder improvements

This branch contains a number of improvements/fixes from the fork of this cookbook that currently lives in omnibus-ruby. The plan is to move the omnibus cookbook out of the omnibus-ruby repo into it's own git repository on opscode-cookbooks. This also means we need to get all the improvements that exist in the omnibus cookbook's dependencies out into their respective community cookbooks.

Improvements include:

* Split monolithic default recipe up - create a platform-specific recipe for each platform family. This will make it easier to add future platforms and make the cookbook easier to maintain!
* Ensure GCC 4 is available on older pre-6 EL
* Add `solaris2` platform family support
* Updated test-kitchen 1.0 support (Vagrant 1.1)