YARM v0.8.6

This is a pre-release for bug testing for the new ore tracker (see #98).

If testing goes well, the next version will be a full release.

Changes

• Separate ore tracking functions to another module. This should be an invisible change, except for adding the ability to globally limit the number of entities queried in a single tick.
• Save/load times may also be affected by the above, as we are now keeping references to actual entities instead of keeping just their coordinates; on the bright side, UPS should be higher, especially for large sites.