Add support for HPCOMBI

[james-d-mitchell]

At present this is mostly disabled and/or not bound, because we wanted to release v1 sooner rather than later. It'd be great to add support for HPCOMBI though, and there is some stuff that will support this eventually already in the main branch.

[james-d-mitchell]

This is largely done in #355 the exceptions are that BMat8 and BMat16 are not yet supported.