* Add IntelliJ workspace files to the .gitignore.
* Add a simple make_example script for Linux.
* Create a `sync` module with many GBA-specific sync utilties.
* Fix overflow error in debug mode in the hello_world crate.
* Fixes to DMA.
* Code cleanup for the sync module.
* Run rustfmt on new sync code.
* Fix up some names and documentation in the sync module.
* Add a few changes suggested by thomcc for the locks.
* Added needed compiler fences to `InitOnce::try_get`.
* Change the error in `RawMutex::raw_unlock` to better reflect the cause.
* Add a proper issue link to the __sync_synchronize hack.
* Disable interrupts during `InitOnce::try_get`.
* Fix some bad wording in the comments for `InitOnce::try_get`
* Use the new target in `cfg` checks to see if we're on GBA.
* Change registers used for transfer_align4_arm for the different target.
* Cleanup on sync_api changes for the target change.
