Un-quiet the CI build to see why it is failing.
Restore jruby.bash script (replaced by binary somehow).
Revert "Un-quiet the CI build to see why it is failing."

This reverts commit 13a151b80e33fd10a1e179c7238ad4d57f0c4181.
Fix regression in StringIO.open and unused imports.

Conflicts:
	core/src/main/java/org/jruby/ext/stringio/StringIO.java
2.0 Enumerator#size compatibility enhancements

Update enum constructors for 2.0, and ensure in a number of cases that
we keep the size when we enumeratorize (note: there's still a number
of other enumeratorize calls which will be addressed in a later commit)