can/must now use latest releases of synthplayer and miniaudio

removed embedded synthplayer, pin library versions

clearer

updating the synthplayer library

don't show the unrevealed cave during an intro txt popup, fixes #8

proper fallback to ffmpeg if oggdec isn't available on the system

updated synthplayer library to improve audio output device selection …

…again

new release 5.3

new release 5.2

fixed python 3.7 compatibility issue in demo playback.

new synthesizer API