Add M × N matrix scalar multiplication support

[chrissimpkins]

Requirements:

• any M by N matrix size
• any supported T numeric scalar type

Properties:

• Associative: where c, d are scalar values and A is a matrix, (cd)A=c(dA)
• Distributive: where c,d are scalar values and A, B are matrices with the same dimension c(A+B)=cA+cB and (c+d)A=cA+dA
• Multiplicative identity: where 1 is the scalar value 1 and A is a matrix 1A=A
• Multiplicative property with zero: where 0 is the scalar value 0, A is a matrix, and O is the zero matrix with the same dimensions as A: 0⋅A=O