Update Swift code for Xcode 6 beta 5

Mostly mundane tweaks for changes to Swift. The two big ones are that swift's
name mangling is now just "module.classname" and that all properties have to be
explicitly declared as `dynamic`.

Closes #733.
But I don't see why we need the ```?? false``` at all in this case. If we removed it wouldn't it function in exactly the same way? I'm still waiting for beta 5 to download so can't test it out.