Fix #1090: Allow exporting classes and modules ending in _=
Merge pull request #1092 from gzm0/export-setter-like-obj

Fix #1090: Allow exporting classes and modules ending in _=
Fix #1072: Bump sbt version to 0.13.5

Also see #1008, #1038.

This re-does eede37cc4fb87db96eae28a9a536c507233f1dd1 and
8f2169a37e77bca4cee8300c638e15d9eca138aa which were
reverted in 353e9635a2276e48b6ea6541e49f6c7ab8763b71.
Merge pull request #1094 from gzm0/bump-sbt-version

Fix #1072: Bump sbt version to 0.13.5
Consider more trees as trivial for inlining.
Improve optimization of IsInstanceOf.
Update checksizes.sh for the two previous commits.
Merge pull request #1098 from sjrd/improve-optimizer

Improve optimizer