Improve Waveform drawing speed

Blender supports video editing through its video sequence editor. While the editor allows users to load videos and audio files, computing the audio waveforms for the audio tracks can take a really long time when working with large files (multiple gigabytes). This makes for a degraded user experience. This project will reduce the time taken to see the waveforms by: ● Processing multiple audio sequences in parallel in the background, ● Only computing the waveforms of sequences that are visible in the user interface Once these initial speed ups are achieved, I'll explore improvement opportunities lower down the audio processing stack.