Add constants from pokecrystal

[rawr51919]

This PR is a proof-of-concept showing what a hardware.inc using constants from pokecrystal would look like. Some of these names can be used for new names for constants down the line, so this one might be a little while before any action comes of this. Fixes #26

[evie-calico]

I don't know if there was prior discussion about this, but I think this would really clutter the file simply to become compatible with pokecrystal. Why not update pokecrystal to conform to hardware.inc instead?

[rawr51919]

I don't know if there was prior discussion about this, but I think this would really clutter the file simply to become compatible with pokecrystal. Why not update pokecrystal to conform to hardware.inc instead?

There wasn't much in the way of discussion about this, yet pokecrystal's PR #943 does exactly that

[evie-calico]

I think rather than updating this file to support every different project's naming scheme, we should get the projects to settle on using hardware.inc

[rawr51919]

Backported a constant addition from this PR to #33, RPB_LED_ON. I had forgot to add it during #31

[rawr51919]

I think rather than updating this file to support every different project's naming scheme, we should get the projects to settle on using hardware.inc

There has also been an issue opened on the subject on pokecrystal issue #914