Missing Stub Invocation API

[jonathan-benn]

The following stub invocation API functions are missing:

stub.yield([arg1, arg2, ...])
# Invoke callbacks passed to the stub with the given arguments.
# If the stub was never called with a function argument, yield throws an error.
# Also aliased as invokeCallback.

stub.yieldTo(callback, [arg1, arg2, ...])
# Invokes callbacks passed as a property of an object to the stub.
# Like yield, yieldTo grabs the first matching argument, finds the callback and 
# calls it with the (optional) arguments.

stub.callArg(argNum)
# Like yield, but with an explicit argument number specifying which callback to call.
# Useful if a function is called with more than one callback, and simply calling the
# first callback is not desired.

stub.callArgWith(argNum, [arg1, arg2, ...])
# Like callArg, but with arguments.

[note35]

This is related to #18, they can be implemented at the same time.