Irb loads spec/resources.rb
Tests need a 'fake' instruments process
Makes spec/Resources class a proper singleton

Required for 'fake instruments' pid tracking. This class should
have been always been a singleton.
Resources can launch and kill 'fake' instruments
Rewrite + specs for terminating instruments
Merge pull request #48 from calabash/feature/more-instruments-killing-work

Rewrite of instruments termination code + tests