[COOK-2505] 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!
[COOK-2505] ensure GCC 4 is available on older pre-6 EL
[COOK-2505] add `solaris2` platform family support
Updated test-kitchen 1.0 support

* Requires Vagrant 1.1, test-kitchen 1.0.0.alpha.2
* Removes Vagrantfile (now handled by kitchen-vagrant 0.7.4+)
* Remove Gemfile (no more Bundler \o/)
* Add TESTING.md doc