Added headless plugin, and fixed audio issue

Added version of the plugin that works in headless.

Fixed audio issue that caused crackling noises, due to the waveform going below -1 or above 1 (seems only happened with remote streams so maybe something to do with Opus), causing overflow when converting to Int16 for wav file. Fixed it by clamping the buffer before conversion.

Also fixed the animatino control visual that broken after a Neos update disallowing arbtirary delegates to be assigned to fields.