Version 3.1.1

Minor release for compatibility with other packages.

Features:

• Subroutine to scale a matrix by a diagonal matrix.
• Matrices to help with preserving symmetry (test symmetry deviation, symmetrize matrix)
• Added a subroutine test_ntpoly_link that sits outside of any module, that can be used to test linking.

Bug Fixes:

• unused be_verbose argument in process grid constructor removed