Add buster.assertions.add() 'macro'
Add buster.assertions.add() 'macro'

- buster.assertsions.add takes care of all assertion plumbing and defines both
  assert.yourAssertion and refute.yourAssertion.
- The macro is used to implement the hasPrototype assertion/refutation as a
  proof of concept
- Most of the assertions will be defined using this macro
- The macro makes it super easy for end-users to define their own
  assertions/refutations that behave exactly like the built-in ones

Power to the people!

busterjs/referee