Loadable hot pixels.

Altering the reconstruction to save/load hot pixels in a text file.

In pyEudetReconstruction.py and EudetData.py
- if the hot pixel file exists, load it
- otherwise find the hot pixels and save the file for next time

This enables later analysis of the hot pixels per run, and also speeds
up reconstruction the second time around.
Removed unnecessary arguement in FindHotPixel.
Fix binning in FindHotPixel.

In EudetData.py:
- fix binning limits in FindHotPixel, had overflow due to one bin too few.
New file: FindHotPixels.py

Added new file which should be used to find the hot pixels of a run.
It's simpler to make the hot pixel file once (here) and then only load
it in ComputeAlignment, pyEudetReconstructionOnly etc.

The file takes regular inputs, and simply calls FindHotPixel.
Control plots are saved. The usual usage would be to call this file,
then ComputeAlignment, then the reconstruction and analysis.
Loading hot pixels in ComputeAlignment and pyEudetReconstructionOnly.

Removed the old calls to FindHotPixel, these files will now only load
hot pixels from a file created by the purpose written FindHotPixel.py
script.
Merge pull request #25 from sredford/master

Loadable hot pixels.