orthogonalize function is broken

[tboggs]

Release 0.21 broke the orthogonalize function during cleanup of import statements. Several numpy calls need to be fixed:

• "identity" should be changed to "np.identity"
• "np.inv" should be changed to "np.linalg.inv"

There should also be a unit test added for the orthogonalize function.

[tboggs]

Fixed by commit bff079a