Remove the dependency on psych and blimpy libraries

I'll be moving more towards vagrant and vagrant-aws in the future
Require the jpm ruby gem to be installed in order for our custom provider to work

jpm is located: <https://github.com/rtyler/jpm>

References #10, #11, #12
setting fsroot to slave_home for the swarm jar
fixing whitespace for rake lint
Refactor some of the rspec-puppet examples for jenkins::slave to be more concise

This reduces some duplication, but also makes sure we have the exact same
branch coverage with the shared_context for both sets of platforms supported by
puppet-jenkins