Sable's Grimoire demo

This is the first version of the demo for Sable's Grimoire. There may be updates to the demo if there are any bugs found, or if an important engine update is released, but I expect that there likely won't be any updates to the demo henceforth.

Development on the full game is ongoing, so any feedback from the demo may be taken into consideration in the final game. The full game is expected to be released in another 4-5 months.