Add Gemfile and .ruby-{gemset,version}
Initial support for test-kitchen

Currently, there aren't any tests present, but it's possible to run
`kitchen converge default-ubuntu-1204` and have a Vagrant box setup
with the bare minimum.
First stab at tests for default recipe

Which is mainly installation of mesos with the correct directories in
various places and whatnot.
Refactor examples for default suite tests into shared examples
Add integration tests for slave recipe using mesosphere

Actually needed a few changes to both `slave` and `mesosphere` recipes:

* Install `libcurl3` package in `mesosphere` recipe as it was needed to
get dpkg to actually install mesos, otherwise it would complain about
dependency requirements that weren't met.
* Use Chef::Application.fatal! as Chef::Log.fatal! doesn't exist in
newer versions of chef, though I think Chef::Application.fatal! exist
in older versions of chef. I'm not sure about this at all.
Add integration tests for master recipe using mesosphere
Add integration tests for master recipe when building mesos from source
Add integration tests for slave recipe when building mesos from source
Add some kind of tests for running mesos-slave when installed from source
Refactor tests regarding configuration of master&slave recipes

shared_examples_for the win.

Haven't actually run the tests regarding source based recipes as they
take about 25 minutes each to set up. I'll get around tomorrow though.
Add blurb about testing to README
Merge pull request #9 from mthssdrbrg/test-kitchen

Integration tests using test-kitchen and serverspec. Thanks @mthssdrbrg!