Few modifications to PropXtalk.C.
   - Updated clover loops to be 1->16 not 0->15.
   - Initialised HitSegment, HitClover, HitCrystal to zero.  There are some events with a seg hit but no core hit, these resulted in an array being indexed by uninitlised HitCrystal which caused a seg fault in some cases, meaningless results in others.

** Note **
There are several problems with the main analysis loop in the crosstalk calculation.  It has gotten complicated and is therefore bug prone.  I will rewrite it soon.
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