v0.9

This release is for ProcJam 2018.

• Changed license to AGPL3+, but also waive rights in case of my death.
• Switched to semantic versioning.
• Made the frontend experience faster by implementing deltas. Use Engine.get_delta(...) to rapidly generate a dictionary describing changes between two points in time in a single branch.
• Switched serialization format from an abuse of JSON to msgpack.
• Improved the API of the ELiDE widgets, making it easier to use them in your own game. See Dungeon University for an example.
• You can zoom the map with the mousewheel now.
• Reduced memory usage for large worlds. They still take a long time to load; I'll work on that.
• Wrote a real tutorial for building LiSE games in Python outside of ELiDE.
• Made the order of execution for rulebooks easier to understand. Basically, rulebooks are followed in alphabetical order; rules within them go in whatever order they were added.
• Rearranged the UI a little.
• You can edit every rulebook in ELiDE now, including the ones that apply to all a character's avatars and so forth.
• Rules will only be followed for entities that still exist when they're run.
• The turn will always increment before running any rules, and no rules will be run on turn 0.
• Various little performance improvements and fixes to things like data integrity.