Bug 910795 part 1.  Add a way to Rebind() an nsString to be a dependent string.  r=bsmedberg
Bug 910795 part 2.  Use the new Rebind() setup to avoid creating string copies for variadic string arguments.  r=smaug
Bug 911771.  Remove uses of MOZ_DEBUG in .cpp files, since there is no such thing there.  Use DEBUG instead.  r=glandium