Squashed spy refactor and new spy syntax

Jasmine spies now have a 'and' property which allows the user to
change the spy's execution strategy-- such as '.and.callReturn(4)'
and a 'calls' property which allows inspection of the calls a spy
has received.

* This is a breaking change *

There is a CallTracker that keeps track of all calls and arguments
and a SpyStrategy which determines what the spy should do when it
is called.