0.1.x.104-dev "Ancient Ascension"

I thought I'd add named releases, starting with "Ancient Ascension."

Additions:

1. LuaJIT 2.0 - This means lua-based scripts will run even faster! ("They've gone to plaid!")
2. Sprite Blitting - Basic sprite blitting is now supported. While the function takes the same arguments as TIC-80, not everything is implemented, yet. You can only draw sprites of arbitrary 8x8 pixel cell width and height. They cannot yet be flipped, rotated, or scaled. Please see example_spr.lua for an example of how to use spr and it's helper function sidx which can be used to determine a sprite index from its sprite page and cell coordinates.

Changes:

1. Started separating code into more files. Specifically, system.hpp has been split into system.hpp (trimmed down mode), system/system.cpp, system/internal.cpp, and system/api.cpp