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