Split uno2cpp.cxx and cpp2uno.cxx into separate files for the emulator
(i386) and device (ARM). Much cleaner like that.

Try harder to get the ARM stuff to actually work.

Add the rtti.h and unwind-cxx.h files from libcppabi as such instead
of cherry-picking stuff from them.

Change-Id: Ia238a9ce048116ad796dfb168fd4e5d3b9712ad5