* remove receive_coinbase fn from wallet to wallet client
* start moving clients into separate mod
* rustfmt
* move wallet client + start listener into wallet 'clients'
* rustfmt
* refactor API to make it more modular and completely decouple sending
* rustfmt
* further decouple API from sending methods
* rustfmt
* remove wallet to wallet client trait
* rustfmt
* rename / refactor client + adapters
* rustfmt
* add adapter concept
* add midding node_clients dir
* add file and null adapters
* rustfmt
* remove receive from owner api
* factor out receiving slates into trait
* rustfmt
* adding listen trait
* rustfmt
* change listener to use trait
* rustfmt
* add test for file-based exchange
* replace http api send command
* rustfmt
* move controller out of libwallet and into top-level wallet dir
* rustfmt
* add moved controller
