017-carpo

This release has two major changes:

1. It finishes the initial integration of the tiered note commitment tree in last week's testnet, so all transaction proofs are now made with the TCT and checked against the TCT anchors.

2. It completely replaces the pcli code with a new client architecture broken into modular services: a view service responsible for syncing the private chain state, a custody service responsible for authorizing transactions, and wallet logic that does asynchronous RPC to a generic view and custody service. This allows chain scanning to be done either in-process or out-of-process with a new pviewd binary. In the future, it will also allow diverse custody setups, like a signing server, hardware wallet, threshold signing, etc.