Add grandSum, sumRows, sumColumns, scalarDivide, scalarMultiply, scalarAdd, scalarSubtract Stream Evaluators

This ticket adds a set of matrix math functions:

grandSum: sum of all the values in a matrix
sumRows: returns a vector with sums of all rows
sumColums: returns a vector with the sums of columns
scalarAdd: add a number to each entry in the matrix, returns s new matrix
scalarSubtract: subtracts a number from each entry in the matrix, returns a new matrix
scalarMultiply: multiplies a number to each entry in the matrix, returns a new matrix
scalarDivide: divides each entry in a matrix by a number, returns a new matrix