Clean: Remove unused modulegraph code and library. This unused code was already included into the python3 branch.
Clean: Upgrade macholib to 1.7, altgraph to 0.12 and pefile to 1.2.10-139.
Clean: Update readme with up-to-date requirements.
Fix: Restore accidentally removed code.
Fix: On OS X pyinstaller fixes the Mach-O headers of EXE to allow code signing.