Compton data updates

[keadyk]

• This PR:
  1.) adds useful const accessors to the Compton class (as well as a unit test for them), and
  2.) renames Compton_NWA -> Compton, hence omitting the controversial hip-hop reference. (No major changes to the interface/purpose of the class)
• Pre-Merge Code Review
  • Travis CI checks pass
  • Code coverage does not decrease
  • Valgrind test passes
  • Toss2 checks pass
  • Toss3 checks pass
  • Trinitite checks pass
  • Code reviewed/approved, sufficient DbC checks, testing, documentation

[keadyk]

One test fails on Moonlight, but this stems from PR #173 (which I merged to my repo before issuing this pull request).

[KineticTheory]

@keadyk I'm going to merge #175, but we really need to have your compton package installed somewhere (moonlight?) so more exhaustive testing can be done as an ongoing process.

[keadyk]

Absolutely. With a little guidance on where to put it (and how to put it there), I can have a beta release up and running on one of the machines for testing sometime next week!