preliminary work with exparay
Add doc, test, and intents for exp_aray interface

NOTE: exparay.f contained mistake:
"b(i,j) = exp(b(i,j))" should be "b(i,j) = exp(a(i,j))"
Add doc, test, intents for multbycnst interface.
Modify awips.py to adhere to Sphinx formatting.
Preliminary work with derivative interface.
Add doc, test, intents for derivative interface.
Add doc, test, and intents for lintrans.f
Add doc, test, intents for dotvectors interface

Also cleaned up documentation from previous commits
Add doc, test, intents for powercalc interface.