Add new helicopter/ directory

The old (helicopter) test project is incompatible with new Eclipse + GNU
ARM Eclipse plugin. I'm not bothering with trying to fix it. Just start
over.

This is a new "blinkled" project, snapshotted right after the project
wizard was complete.
helicopter: add changed Eclipse files

I'm not sure what exactly changed, but .cproject and
.settings/language.settings.xml do have lots of changes.
helicopter: add the Syma S107 IR protocol decoder code

Copied from somewhere else in this repo...