Mandatory Multisig

[thelink2012]

Closes #28

Issue: Broadcasting using coinb.in doesn't work properly for these transactions, using blockchain.info though goes just fine. So there's something that should be fixed on the backend I guess.

[OutCast3k]

Hmmm. This is really cool.

I will review your code and look into the issue with fixing the backend so it accepts the signed transaction and then accept your request to merge.

Nice work.

[neurocis]

Agreed, very cool, will be reviewing and testing this tonight for PiggyCoinb.in :)

[weex]

@OutCast3k Coinb.in itself is really awesome and desperately needed if people are going to trade safely in a trustless manner. I was thinking a more general construction with logical and/or in it might be good but thelink2012 nailed it by designing this as multisig with a mandatory component which is the only use-case I need supported and was probably a lot more straightforward to implement. Looking forward to see this merged.