- Remove "Buffer" suffix from some byte and word quantities
- Change "Ptr" to "Pointer"

Fixes #789

Use explicit ldh instruction to access HRAM locations, don't rely on optimizing ld

Introduce MONICON_* constants
Introduce BATTLEPLAYERACTION_* constants

I have no idea why this was a thing (do people store this repo on FAT32
flash drives or something?), but quite a bit of files had a permission
of 755. This isn't really a problem, but it's inconsistent and weird.

This is an informed attempt at reorganizing the engine/ directory by
creating categorized subdirectories, in order to make it easier to
navigate and find things.

The directories created are as follows:
* engine/game: Contains all "minigames", things like the unown puzzle
and slot machine.
* engine/gfx: Contains all handling of graphics. From loading palettes
to playing animations.
* engine/link: Contains all multiplayer functionality.
* engine/menu: Contains all generic/misc. menus and menu code.
Other, more specialized menus are in their own subdirectories (pokedex,
pokegear, party menu, etc).
* engine/overworld: Contains all handling of the overworld. From loading
and connecting maps to wild encounters and the scripting engine.
* engine/pokegear: In the same vein as engine/pokedex, except it could
use some more splitting up.
* engine/pokemon: Contains everything related to manipulating pokemon
data. From the pokemon storage system to evolution and mail.
* engine/printer: Contains everything related to printing things as well
as the printer communication.
* engine/title: Contains intro sequences, title screens and credits.