Don't waste time concatenating strings
Revert "Cleanup for merge", bring back singlethreaded play_classify

This (partly) reverts commit 1d2ce073c68c516df7f6b6a7607751e2d15d56f3.

Conflicts:
	src/blindtastic_models.h
Move calculation of characteristic weight

(This will facilitate future work where we only care about half the grid)
See the difference between grass on the left and grass on the right.

+ fix: print location only once per frame
+ improve readability of some var names