Merge 2.10.x into master

Conflicts:
	src/compiler/scala/tools/nsc/typechecker/Duplicators.scala
	src/library/scala/concurrent/Future.scala
	test/files/jvm/scala-concurrent-tck.scala
No-op merge #2655 into master (already ported as #2683).
Merge 2.10.x into master

Conflicts:
	src/compiler/scala/tools/nsc/typechecker/Namers.scala
	src/partest/scala/tools/partest/PartestTask.scala