Rename MaxCounter -> MaxPosInt in the places I forgot.
Some progress on Data.LVar.Counter.
Typo fixes.
Mergesort builds.
Revert "Mergesort builds."

This reverts commit 0831285610758f844d305335b5e7f6ead4c80862.
Add PLDI paper to docs
Merge branch 'master' into 2.0

Conflicts:
	haskell/lvish/Data/LVar/Counter.hs