Fixed incidence angle for SAC header

[damhuonglan]

What does this PR do?

Fixed incidence angle for SAC header such that the result is angles from the vertical axis instead of horizontal; Added test case to check that the CMPINC field in the header of the written SAC file;

Relevant Issues?

469

Checklist

• [ ] This PR is not directly related to an existing issue (which has no PR yet).
• [ ] All tests pass.
• [ ] Any new or changed features have are documented.
• [ ] Changes have been added to CHANGELOG.txt .
• [ ] First time contributors have added your name to CONTRIBUTORS.txt .

[hrotman-pic]

Thank you for creating this PR. I tested it, and it meets the requested behavior of CMPINC=90 for the horizontal channels, but unfortunately does not meet the requested behavior for CMPINC of the vertical channel. For the vertical channel, I think ph5toms may need to look at the orientation/description_s field in the receiver table, and if orientation/description_s=Z, I believe SAC dip = dip + 90 will give the requested CMPINC behavior for the vertical channel. For most sensors used in PH5 experiments, orientation/dip/value_f=90 for the vertical channel, so this would result in 90 + 90 = 180 CMPINC on the SAC header. For sensors with the opposite convention, orientation/dip/value_f=-90 for the vertical channel, so -90 + 90 = 0 CMPINC on the SAC header.