First couple of tests

Having manually installed GTest to usr/local
Audiodata done, Chromagram mostly done
Binode
Shift factory wrappers into private space
Bugfix LPF delay
Refactor and tests for LPF and downsampler

LPF tests are a bit shit, and the new logic has slowed things down a
bit (but gained lower coupling and mathematical defensibility) and very
slightly changed output (e.g. Kingdom by Spor); be sure to run the
original hundred for reference.
FFT Adapter test
const
Begun adding identifiers in header prototypes; easier to work with in IDEs.
Finished header identifiers, added shortcut to LPF
Adaptive tuning test