Clean up setup.py: libraries are required, duplicate code removed, docs, etc.
Clean up setup.py: libraries are required, duplicate code removed, docs, etc.

markreidvfx/PyAV,PyAV-Org/PyAV,mcpv/PyAV,xxr3376/PyAV,PyAV-Org/PyAV,mcpv/PyAV,xxr3376/PyAV,pupil-labs/PyAV,danielballan/PyAV,danielballan/PyAV,danielballan/PyAV,mcpv/PyAV,xxr3376/PyAV,pupil-labs/PyAV,mikeboers/PyAV,markreidvfx/PyAV,pupil-labs/PyAV,pupil-labs/PyAV,markreidvfx/PyAV,mikeboers/PyAV