Single file build

[Weldify]

I've been having a blast for the past few days with nico, although one thing that bothers me is that I can't do single file builds. The main pain points for me are:

1. Having to provide SDL2 myself - perhaps could it be somehow be automatically embedded instead?
2. Having to keep my assets in files - I prefer to store all my assets in binary form via embedfs, but the nico API doesn't provide any functionality for loading assets from memory