Added CountPixelMapRepeats function.

In ToolBox.py:
- added new function CountPixelMapRepeats. This counts how often
the pixel map is repeated before there is a new event. It is the
old 'scaler' variable, which was thought to be 15 but is shown to
be never more than 15 but often less. This shows that we shouldn't
use a 'scaler' variable, but rather check for when there's a new
pixel map by hand.

In pyEudetReconstructionOnly.py:
- call this function and save histogram
Removed unnecessary print statement from CountPixelMapRepeats.
Alteration to FilterHotPixel to no longer depend on scaler.
Also renamed to FindHotPixel, since this function doesn't
filter (that's done in ClusterEvent).

In EudetData.py:
- rewrite of FindHotPixel to avoid scaler, whilst still taking
into account repeated pixel maps
- two additional debug histograms, for hit pixels and nhits
- catch incase the tbtrack file doesn't have 10000 events

In pyEudetReconstructionOnly.py:
- change call to FindHotPixel
- save two additional histograms

In pyEudetAnalysis.py:
- change call to FindHotPixel

In ComputeAlignment.py:
- change call to FindHotPixel
- change order so n_proc is defined in time for FindHotPixel
Merge pull request #12 from sredford/master

Added CountPixelMapRepeats function.