some bugfixes
Ported the new stuff into ROOT plots, matplotlib ones need changes
Merge pull request #22 from senkin/master

experimental -> src
adding uncertainties (part 3)

- updated 03_calculate_systematics.py, only missing ttbar theory systematics now
- added tuple (value, error_low, error_high) to Graph conversion
- added systematics calculation
bug fixes
adding ttbar theory systematic