Feature/algebra

Okay, main changes:

Tests for CSCMatrix Operators under OptimizationSpace
FrobeniusMatrixNorm is better
Minor refactor to CSCMatrixOps 

Okay, I'll add in the non-zero element operations for Div, Pow, and Mod, which will make second operand matrix zeros into throws Exception (Int) or Infinity (Double), 1, and NaN respectively.

Makes sense that zeros are skipped for multiplication since you'd assume the zeros will remain zero.