Update 0.20

A very small update with no new content, just bug fixes and a couple important features:

- Save Progress: Whenever you rest in the bed your progress will be saved. This first implementation just overwrites the last save, but I can add save slots later.

- Web support for Mac: I've updated the engine and the latest version should be playable on Mac. I don't have a Mac to test this so if anyone has issues please let us know.

That's it. Next update I'll focus on adding new content instead, but these were things I wanted to get out of the way before going any further.