Renamed libmach_triple to libmachine. Moved about half of libsyntax/abi
to libmachine. Added convenience checks for Android triples (I apologize, I
trapped myself on my own work-flow).
Use libmachine/triple in compiletest.
Fixed passing wrong rustcflags to compiletest.
Fix test warnings.
Compiletest: if flagged, build for both target & host.