created Key type and modified all protocol objects to use it instead of
byte slice. working on implementing key creation and signing.
updated protocol (v2 pubkey and v3 broadcast) and fixed build errors
fixed key encoding/decoding and added test. fixed sign func and implemented verify (with sha1 digest
hide auto-generated version and special vals
split payload into more appropriate named files. moved constants around.
Created NewBroadcast constructor function.
added some sigining/verifying tests with sigs from PyBitmessage.  Seems to be working
merge. Updated protocol, implemented ecdsa signing