Added // NOLINT in matrix_exp_pade to stop error messages from cpplint when it goes over the code from Eigen/unsupported.
Added // NOLINT in matrix_exp_pade to stop error messages from cpplint when it goes over the code from Eigen/unsupported.

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