[RELEASE] Releasing version 0.1.2

Changelog:
  * More complete README
  * Fix Python package long description (use README.rst)
  * ReadTheDocs integration
  * Integrate extra folders in distribution (test, demo, docs)
[DEMO] Update biquad filter design demo with phase view instead of linear amplitude
[DEV] Fix biquad filter flat frequency response
[DEV] Add rectangular analysis window type and stop using arrays in analysis module
[TEST] Add unit test for all pass biquad filter
[DEV] Add single pole filter

With unit tests and filter design demo.
[DEV] Rename AnalysisWindow class to Window
[DEV] Add state variable filter
[DEMO] Add state variable filter design demo
[DEMO] Enhance state variable filter design demo with legend
[DOCS] Better docstrings for filter module
[DOCS] Enable sphinx autodoc for class __init__ method
[DOCS] Add docstrings for all modules
[DEV] Fix variable naming convention for complex module
[DEV] Fix variable naming convention for conversion module
[DEMO] Fix filter reset and overshoot in state variable filter design
[MISC] Fix indentation and unused import in filter module
[DEV] Add parametric equalizer in filter module (with unit tests and demo)
[DEMO] Fix limits in parametric equalizer design demo
[MISC] Include homepage link in README