ARMORY-225 - Multisig unit tests

Rewrite the blockchain creation script such that it uses deterministic
signing (RFC 6979). Along the way, deterministic signing was made the
system default. (Code is untested for now and is primarily meant to get
other team members going on other changes they wish to make.)
Merge branch 'dev' of github.com:etotheipi/BitcoinArmory into dev