No change to PGL, just the test suite for Homebrew

Bump to 0.97, lots of changes/fixes since 0.96

Besides, now that people are actually using it/packaging for things like
homebrew (https://formulae.brew.sh/formula/portablegl#default),
I need to start properly tagging for "releases" since they're getting
ancient 0.94 the last time I created a tag

Fix glBufferData bug which broke glDrawElements

Make default shader safe if no uniforms set

pglResizeFramebuffer() now returns backbuffer ptr

Decided to start tagging when I update the version