added a method to remove all callgraph edges starting at a specific unit
added a method to remove all callgraph edges starting at a specific unit

xph906/SootNew,anddann/soot,mbenz89/soot,plast-lab/soot,xph906/SootNew,cfallin/soot,xph906/SootNew,xph906/SootNew,anddann/soot,anddann/soot,cfallin/soot,mbenz89/soot,anddann/soot,plast-lab/soot,cfallin/soot,mbenz89/soot,mbenz89/soot,cfallin/soot,plast-lab/soot