Excise hardcoded Vec4F

...unit tests need some work

Making variable-length vectors isn't too hard maybe

Refactored function type a little.

On the whole I think this might have been a lateral move,
but oh well.

Passing through, making some notes

update deps

Fix some minor clippy lints

literals, some simplification, etc

Noodling around with parser a little.

cleanup

Update test fragment shader to return a vec4

Define vector4f type.

You can't actually do anything with it at the moment except
construct it, so it's pretty easy!  But hopefully that will
be enough to get a shader actually functioning.

Add location annotations to inputs/outputs.

heckin' backends

Working on an example.

Would be easier if I had vectors!

Entry points work.

Well the compiler command-line program works now!

Just can't, you know, get anything useful as input.

Main program, woohoo!

Doesn't actually do anything yet, natch.

Holy cats I think if statements work!

Girding my loins to do if statements.

Refactor unit tests some.