Unit tests for addition/subtraction of a scalar with a matrix/vector with doubles.
Unit tests for addition/subtraction of a scalar with a matrix/vector with doubles.

stan-dev/math,stan-dev/stan,stan-dev/math,stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/math,stan-dev/stan,stan-dev/stan,stan-dev/math