introduces Invokable Statements on edges of the call graph to know the target of a specific invokable statement. closes #483
moves clinit invokes from the constructor invoke to corresponding new statements before the call, to support clinit calls caused by arrays or multiarrys
call graphs will save a list entry methods
clinit calls of given start methods are added to the entry methods of a call graphs
the edge between a starting method and their corresponding clinit method was removed fixes #902