Rewrote library creation for audio and visual stimuli to have less binary dependencies
Include text-to-speech to reduce binary dependencies (but add dependency on pyttsx3)
Include a data directory for binary media
Switch to `from pkg_resources import resource_filename` for easier installation
Include a preliminary low-level tts interface to create audio files on demand
Increase coverage of documentation
[Full documentation](https://reiz.agricolab.de/)
v.0.3.3rc