Implemented button_c, unit tests.
Shelled button map module.
Replaced raw uint_t with button_id_t.
Implemented button map up through default ctor, unit test.
Merge branch 'master' of github.com:fsecilia/axiom-terminal-raw-input

Conflicts:
	lib/inc/axiom/terminal/raw-input/terminal-raw-input-button.cpp
	lib/inc/axiom/terminal/raw-input/terminal-raw-input-button.hpp

Apparently I amended a pushed commit, but didn't force. Meh.
File rename.
Simplified naming: removed "terminal-raw-input" prefix where unnecessary.

This naming scheme was originally used to prevent a future collision with
normal, non-terminal button input. We'll refactor when that's necessary.