Major refactor of settings. Added plenty of more files.

- Settings in the training process has been moved to a config file.
- Created an abstraction for binary descriptors, and added support
  for both edges and parts.
- Added supported for training from VOC files.
- Added a simple score function, to give some quantitative evaluations.
- Added functions for extracting positives and negatives to fixed size.
- Resizing is done with pre-filtering now.
Better bins in plot_score_file.py.