Raw mptx support

!!! this is built on top of mastercoin-MSC/mastercore#102 !!!

This provides the ability to send a raw hex string to the rpc with sender and reference addresses.  the raw hex string is interpretted as a raw master protocol packet and core will chunk it out and do all the necessary encoding.

Included with this is refactoring of the class B sending code to support more than a single sigs worth of data.