bin/shell.sh now warns you if jar is missing
have language tests ensure tmp directory exists

usually something has made it by the time it's needed,
but I intermittently find that I don't have it when
I want it
remove unused code
update extension builds to work on Travis
fix spaces-in-path bug in extension builds
make a 2.11 deprecation warning go away

committing this on a 2.10 branch because I think it's a code
improvement even on 2.10; it makes the code's intent clearer
make a 2.11 warning about inferred 'Any' go away

committing this on a 2.10 branch because I think it's a code
improvement even on 2.10; it makes the intent clearer
Merge remote-tracking branch 'origin/headless' into tortoise