I Added Better Audio Processing and Nested Rendering to my Game Engine

What the title says. I added better audio processing and nested rendering to my game engine.

Engie now uses float32 audio, and proper decibel mixing using exponentials and logarithms. Volume control is also exponential, to match how ears work. I moved audio processing into the channels, so the audio can focus on interfacing with SDL. Audio and clips now support any WAV format that SDL supports.

Engie now also has a nested rendering system. Each renderer is called a “canvas”. Canvases may be nested, such that draw calls relative to a canvas will propagate up the tree to the graphics and SDL window and renderer. I also added support for tilesets and tileset-based ascii text rendering.

Known bugs:

• There is a single quiet pop the first time audio plays in a program.