Fix build and address some runtime issues#10

Open

dsgrieve wants to merge 10 commits intokcpeppe:masterfrom

dsgrieve:master

Commits on Aug 29, 2019

Test...
David Grieve
committed

Commits on Aug 30, 2019

compile for 11+
David Grieve
committed

Commits on Sep 3, 2019

fix runtime errors
David Grieve
committed

Commits on Jul 13, 2022

fix build
David Grieve
committed
fix ui somewhat
David Grieve
committed

Commits on Jul 14, 2022

changes to get this to work (somewhat) with -Xlog:gc+region=trace
David Grieve
committed

Commits on Jul 18, 2022

step back/rewind then forward again would leave grid visualization in wrong state
David Grieve
committed
previous commit didn't exactly do what it says
David Grieve
committed
remove debug print
David Grieve
committed
Add a legendary legend
David Grieve
committed