Automatic binning

[kreczko]

Automatic binning

• added helper functions (purity, stability) + unit tests for them
• added main script (00_pick_bins.py) + tests

Reorganised tests

• deleted obsoletes
• merged tests that belong to one module

Other

• updated binning plots (synchronised with AnalysisSoftware)
• updated rootpy

This pull request is NOT ready to merge. We need to discuss the bug regarding the differences in purity, stability and N events between what is done in the script and what is done in the helper functions.

[kreczko]

Ready for merging.
test/cross_section_measuremen_00_pick_bins.py is still failing, expecially the number of events requirement:

Traceback (most recent call last):
  File "test/cross_section_measuremen_00_pick_bins.py", line 176, in test_n_events
    self.assertGreaterEqual( N, self.n_min )
AssertionError: 384.0 not greater than or equal to 400

======================================================================
FAIL: test_n_events_reduced_spread (__main__.Test)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "test/cross_section_measuremen_00_pick_bins.py", line 186, in test_n_events_reduced_spread
    self.assertGreaterEqual( N, self.n_min )
AssertionError: 268.0 not greater than or equal to 400

This needs further investigation into how purity, stability and N-events are calculated using the two methods:

1. When creating the new bins
2. after re-binning with the new bins

Generally the numbers do not agree.