#3 and #4 create map and inferable mapping methods for public usage

Again on the message reporting: if we handed in ```method``` (the SourceMethod for with a parameter mapping is created here) to the forgeMapping method and then pass it to the constructor of ForgedMethod, we'd be able to keep the reference in a forged method to the origin real method (-declaration).
If we later continue to extend the forged methods to other mappings that iterable/map mappings, we would already have something in place to keep the possibly longer trail to the origin method. 

WDYT?