Add view to nonZeros of SparseMatrix

Submitted by Darcy

Assigned to Nobody

Link to original bugzilla bug (#1271)
Version: 3.4 (development)

Description

DESIRED FEATURE:

The ability to call a method that zeros the coefficients in a sparse matrix.

Currently the setZero() method zeros all allocated memory but it would be nice to set the Aij coefficients to zero, while keeping the row and column arrays allocated and populated.

Blocking

#1104