* Replace logging backend to flexi-logger and add log rotation
* Changed flexi_logger to log4rs
* Disable logging level filtering in Root logger
* Support different logging levels for file and stdout
* Don't log messages from modules other than Grin-related
* Fix formatting
* Place backed up compressed log copies into log file directory
* Increase default log file size to 16 MiB
* Add comment to config file on log_max_size option
* beginnings to testclient implementation for more complete wallet API testing
* rework TestWalletClient to be message-based proxy
* test fix
* wallet tests now exercising the API directly as much as possible, capable of instantiating multiple wallets
* test in place to run both file and db wallets
* ensure all wallet api functions lock wallet as needed. Split up transaction creation from posting to chain