Added CPS example and fixed loading

[rwalkerlewis]

• Added SerialGridSearch.DoubleCouple_CPS.py , an example showing use of CPS greens functions.
• Fixed loading issue for CPS greens functions (using test data directory structure).

[rmodrak]

@rwalkerlewis, thanks for contributing this test of the CPS client. I'm not sure why the commit history has gotten messed up. Perhaps let me try myself again in a new PR

[rwalkerlewis]

@rwalkerlewis, thanks for contributing this test of the CPS client. I'm not sure why the commit history has gotten messed up. Perhaps let me try myself again in a new PR

I am trying to build a CPS based inversion to serve as results for a test and having a devil of a time doing it. First the CPS tutorials weren't available, now I am finding that they don't work without massaging.

The test is NOT READY.