Move all packet handling, etc., into the mysql.protocol sub-package

[Abscissa]

Purely internal cleanup.

Currently, there's code all over the place that directly handles communications packets. This should all be encapsulated into one spot withing the mysql.protocol sub-package.

I'm marking all such instances with:

//TODO: All low-level commms should be moved into the mysql.protocol package.

[Abscissa]

There's still a LOT of internal cleanup needed, but this much at least is taken care of now and opens the door for all the upcoming cleanups.