Consider alternative Assertion pattern

[bitPogo]

Description

The current implemented Assertion feel wrong, aesthetically and and from the handling since they combine actual arguments and boundaries.

Consider instead doing:

assert(mock._someProxy) { hasBeenCalled().times(42) }

or

assert { mock._someProxy.hasBeenCalled().times(42) }

or similar.

This could be a better fit. Additionally this should deprecate the current Assertions and verify. Also consider a non breaking renaming of the current methods of the verifiers to fit the overall naming convention and since they currently act like assertions.

[bitPogo]

Done with release 0.2.0-rc01