Add regularization routine (differenceRegularize) to numberCounts routines
Add regularization for fits.

* regularize_alpha parameter in spec files now turns on
  Tikhonov style regularization using a derivative operator
  supplied by the models.
* In the 2D case, the regularization is only applied to the 1D model piece.
* Added the appropriate parameters to set this, write it to HDF5,
  pass it through MPI, etc.
* Bump version number to 0.3.3