Feature: test-net support

[mrz1836]

• Requires new go-bitcoin v2
• Update any models that are looking at addresses, destinations or other strings that might be different
• Broadcasting package support
• Paymail (internal support - IE: running a paymail server)
• Paymail (external support - IE: interacting with external service providers, like MoneyButton)

[icellan]

Do you run a Bux server on a net (mainnet, stn, testnet) or do you allow to register an xpub on any net and derive all actions from that?