fmt::Show for Os in libsyntax.
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.
Build syntax extension aux crates for both target & host.
Updated tests.
Replaced 'force-host' with 'needs-host'.
Removed all 'ignore-cross-compile' instances.
Removed many 'ignore-android' due to inability to use syntax extensions.