Merge Dev v2 into v2

[jclapis]

Lots of improvements to merge in:

• Proper support for the nonce, print-tx-data, and sign-tx-only flags
• All of the API routes now provide proper HTTP status codes with JSON-encoded errors
• All of the API routes have had their "RequireXYZ" functions checked so they only require what they need
• API routes, node, and watchtower now properly refresh the contract bindings any time there's an update thanks to Kane's new protocol.version string on-chain
• Updated dependencies and NMC
• Multi-TX functions that need token approval (like RPL swap and stake) now function properly