Use new rspec
Use spawner which borrows from mcmd gem code

This also required that the test suite be better
able to handle tests that run much faster.
Send shell to Servers when created
Mock bundler in tests to speed up tests significantly
Move simplified propagator back to where it came from
Add sudo command stubbing and use Spawner everywhere
First world problem: tests too fast, colliding on seconds now.

Only change the release folder timestamp for tests
Don't use systemu anymore