Indented call to EdgeEfficiency so this only happens if there is a non-zero edge width.
This avoids axis errors when making the histograms.
Bug fix and tidy of EdgeEfficency.

In pyEudetAnalysisOnly.py:
- better save names for plots
- save plot of the total track distribution per edge
- write all 'per edge' plots into root file

In ToolBox.py:
- bug fix: edge_tracks[i] were being filled with only matched tracks. Fixed to fill all tracks.
- better variable names
- return edge_tracks
Cosmetic changes to TrackClusterCorrelation and pyEudetAnalysisOnly.py.

In ToolBox.py:
- better histogram names for TrackClusterCorrelation
- removed unnecessary index and enumerate

In pyEudetAnalysisOnly.py:
- changed order to better follow code
- improved some histogram titles
Merge pull request #5 from sredford/master

EdgeEfficiency indentation and bug fix, plus general tidy of pyEudetAnalysisOnly.py