General purpose mover / goto plugin.
Replaces the old solver based `comehere` in miner.js.
Instead, directly based on mineflayer bot apis and pathfinder.
This makes it simpler and easier to debug.
While less general, pathfinder is sophisticated enough for most cases.
For anything that needs moving from point A to point B.
Such as:
- following
- go to a location
Not in scope: locations and places. Would be a separate plugin.
