Don't overload Audiodata accessors and mutators
Audiodata deque implementation
Downsampler into AudioData
AudioData iterators
AudioData iterators into LPF

Plus force monophonic
AudioData iterators into SpectrumAnalyser
No dynamic allocation for AudioData
Workspace, inc singletons for LPF buffer and FFT adapter
AudioData test extension
Chromagram verbose exception
const ChromaTransforms

Plus style and memory leaks in tests
const LowPassFilters
Typo
Downsampler shortcut test
FFT adapter test
Expanded Parameters test
Expanded KeyClassifier test
const CustomToneProfile
Cleaner setCTP
Factor out preprocessing