Fix stuck notes on panic or all-notes-off.
Merge pull request #1084 from caoliver/stable-1.1

Fix stuck notes on panic or all-notes-off.
Monstro: optimize
use stack for rendering envs/lfos - this allows us to render them in advance which in turn seems to allow better optimizations by compiler
Merge pull request #1094 from diizy/stable-1.1

Monstro: optimize
Merge pull request #1095 from LMMS/stable-1.1

sync