* Rename wallet 'receive' to 'listen'
* Handle use of previous 'receive' command gracefully and clarify docs
* Move listen port from main wallet config to subcommand and break input out into own file method
* Clean up arg description
* Add placeholder to docs for file method in wallet
* Tidy wallet help text
* Rename pending wallet 'receive' to 'request'
* Restore receive method for file based transactions
* "wallet init" to create the initial wallet.seed file
* cleanup and better error msgs
* add some basic wallet docs
* cleanup and make passphrase optional