Appears to be working not. Fixes #1488.
Fix regression in fiber specs; check fiber queue for aliveness.
Reinstate executor thread pool for running fibers. Fixes #1443.
Avoid double-indirection for fully-synchronized locks list.
Avoid creation of null weakref on every ThreadContext.
Merge remote-tracking branch 'origin/jruby-1_7'

Conflicts:
	core/src/main/java/org/jruby/util/cli/Options.java