~vladh/hare-hazel

add contributing section
move shaders into files
change vendoring strategy
refactor to use global per-module state
change licenses to REUSE
add new bindings
update hare-sdl2
cmd/peony: update SDL2 init flags

The names were changed in hare-sdl2 upstream.

Signed-off-by: Drew DeVault <sir@cmpwn.com>
update hare-glm version