Move the Cortex-M specific registers into cortex_m3 directory.
Copyright header
Merge pull request #9 from bharrisau/armregs

Move the Cortex-M specific registers into cortex_m3 directory.
Removed deprecated interfaces.
Various cleanups and documentation changes
Use 'use' instead of 'mod' for scb.
Ported zinc code to std.
Removed core crate reference from app_sched.
Fixed crate_id regexp to detect std lib crate ids.
Added a force-native build option that ignores target.
Switched build from rust-core to libstd.
Removed rust-core.
Ignore thirdparty.
Rake will now fetch rust and patch libstd/liblibc.
Added pin names for mbed board

That code doesn't actually work, but I'll let it be in there for some
time, so that I can stop looking into mbed schematics.
UART's "no parity" is now Disabled instead of None.
Added more useful APIs to GPIO

 * level() returns input gpio level;
 * set_direction() changes gpio direction.

This code makes use of #[deriving], binding zinc to libstd.
Added DHT22 driver and demo app.
Updated readme
Fixed misnamed getter in gpio code.