Enhance method signature matching

[aalramadan]

Stereocode builds a signature map of all methods in a class (including inherited methods) that can be used to filter calls. Currently, the tool does not differentiate between overloaded methods. For example, the following two methods:

void foo(int x, int y)
void foo(double x, double y)

Will have the same signature. That is:
foo(,)

Ideally, it should form two different signatures, but it could be tricky, especially for matching calls within a method.