[project/Xcode] Set deployment target to 10.9.
[project/Xcode] Set deployment target to 10.9.

 - Also, tidy up some project file settings.


apple/swift-llbuild,apple/swift-llbuild,apple/swift-llbuild,apple/swift-llbuild,apple/swift-llbuild,apple/swift-llbuild,apple/swift-llbuild