rf12registry 0.1.0 update

@jcw,

Mostly additional files so should not break anything existing. 

This patch adds ability to write to jeenode rf12demo (compatible) sketches via various simple transports.
I ripped it from my v0.2.0 build (of this feature), but tested on a vanilla housemon (your updated develop branch) and it seems fine.

I'm running a bit hectic here at the moment so the documentation is woefully lacking - I'll flesh it out on my github before I merge it into the document stubs I provided in this patch, I'll then create separate pull to update docs. Will wait till I get feedback from users first tho.

Because of Wimbledon today - I have had little time, to get these docs as I want them, but I realise that some are eager to have this facility this weekend, so hey ho...pat on the back to Murray - now off to man the barbecue.
currently all here: http://thedistractor.github.io/housemon/rf12registry.html
but will split it into seperate docs tomorrow evening.

--lightbulb