Add the API to receive hdcc values

[jpcima]

This is so synth UIs can manipulate sfizz controllers with full precision.
New API: sfizz_send_hdcc

@rghvdberg

[paulfd]

We could argue whether a new name is necessary rather than an overload. I think that it's better to have a different name, since it could be maybe confusing for the value 1. I believe overload resolution would prefer the integer version in this case?

I have to admit I had in mind to deprecate the uint8_t version of the API at some point after the change to float in the internal engine, and let front-ends do their normalization if necessary. VST3 sends normalized CC already IIRC. Keeping both APIs does not make it very clear that we're basically converting the uint8_t to float internally.

[jpcima]

We could argue whether a new name is necessary rather than an overload

Overloading is preferably avoided, in general. It introduces selection and masking problems.
This makes the compiler's job harder, and the programmer's job as well, just as you have noted.