remove extra blank lines before docstrings

To be consistent, remove any blank line between the
class declaration and the associatd docstring.
splat.scales: tidy-up and add docstrings

* rename Scale.base to pitch
* remove degrees, there are only steps
* add Scale.key property
* add Scale.f0 property
* give more flexibility in initialising the scale by not
  inforcing fixed steps
* LogScale: calculate each frequency directly in get_freq
* HarmonicScale: fix rounding errors by not using the math.pow
  function, and create more even steps by centering them around
  the fundamental frequency
* add docstrings everywhere
test.py: add ScaleTest

Add basic tests cases for LogScale and HarmonicScale.
doc: add section about scales

* add general section about scales
* add sub-section to define scale concepts + small example
* add sub-section about scale objects

+ add Beep in introduction
test.py: add ScaleTest

Add ScaleTest class with basic tests cases for
LogScale and HarmonicScale.
splat.scales.Scale: add abs_cycles to use absolute notation

When Scale.abs_cycles is set to True, the notes naming convention
uses absolute cycle numbers which is independent of the key.  The
pitch note is in cycle 4 (so A4 is 440 Hz with default
parameters).  Defaults to False.
doc: scales: add absolute notation + review
test.py: ScaleTest: add cases for relative notation
_splat.c: define audio_formats

* add _splat.audio_formats
* import _splat.audio_formats into splat
* remove duplicate audio_formats in splat/__init__.py
build-0014