Import Swift 3 overlay from swift repo#89

Merged

MadCoder merged 2 commits intomasterfrom

das-swift3-overlay

Jun 22, 2016

Commits on Jun 22, 2016

import Dispatch overlay and apinotes from swift-3.0-preview-2-branch of github swift repo
das
committed
add new overlay sourcefiles to Makefile.am (does not build)
das
committed