paypro: fix how merchant data is stored.
paypro: fix a lot of aspects of storing merchant data in txps.
paypro: remove old code.
paypro: more merchant data storage. createTx and sendTx work.
paypro: fix a lot of errors in payment protocol implementation.
test: fix wallet test if copay is in ./node_modules.
paypro: fix more payment protocol errors.
paypro: add hideous test for payment protocol.
paypro: clean up test.
paypro: clean up test again.