Place treasure/hints, animation and interaction need work

Treasure and hintboxes are absurdly large to make it easy to find them
while debugging.

Tasks:
- Add flare.png for particle system (didn't get committed)
- Add 'win' element to index.html (didn't get committed)
- Check for collision rather than click? Can't see pointer...
- Animate upwards to MAX_HEIGHT_DISPLACEMENT then toward treasure?
Define treeLoadCallback outside loop body

No change in functionality
treasure chest without material
sorry forgot to add the treasure chest and flare files. here ya go
Simplify treasure/hintbox loading sequence

Treasure location is determined in the first scene.executeWhenReady
callback and passed to the functions that need it.
Pull startRenderLoop definition into createScene

No change in functionality.
Subjective decision since many other functions could be moved there as
well, but it's nice to keep all the short callbacks in one place.
Delete unused and useless functions

No change in functionality.
Apply texture to treasure

I'm curious if there's a way to handle treasureBox and treasureLid
together rather than separately in the importMesh callback.
Add missing 'win' div
Merge branch 'treasure-and-hints'

Conflicts:
	js/world.js