Use nullptr instead of NULL.  Still debugging.
Fix indexing bounds bug in fourierFilter
Always test against min, even if max is satisfied, in histogramming.

* Could cause bug if the min was the first element in the array,
  since that would be used to set max but not min (doublebeamHist::fill)
* Add exception check against out of bounds index in histogram.
Merge branch 'nullptr'

Conflicts:
	src/doublebeam.cc