Cleaned up Graph implementation
Cleaned up Graph implementation

Signed-off-by: Tim Henderson <96597d1a2ce50fc967745fc8f11359736ad2bda4@gmail.com>

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