Optimize Harfbuzz-Pure.

Fix segfaults & include test assets (major refactor).

Add documentation & corrected type signatures.

Add, test, & fix shaping function.

Fix build linking errors (mostly by upgrading GHC).

I'm now running on this on elementary OS Jolnir.

Try wrapping HarfBuzz C++ functions in C functions for calling convention/linking issues.

Committing so I can try building on a newer OS.

Implement conversion from functional Buffers to imperative Buffers.