* Adding output stats from plugin, when available
* adding grin config
* moving pow crate from core/pow to it's own crate
* moving POW/mining stuff into pow module, and removing mining dependency from chain
* refactored most of mining into pow module...miner.rs still in server
* update grin tests
* updating genesis block mining to use configured miner, if available
* chain tests back into chain, done with pow refactor
* use tag of cuckoo-miner for pr
* playing around with changing cuckoo sizes on the fly
* modifying tests to use global cuckoo parameters, and checking results
* check for pow size
* Changing global function names, and removing length from POW serialization
* Adding ability to serialise parts of the header, pre-nonce and post-nonce
* Some test integration of queueing functions in cuckoo-miner
* more cuckoo-miner async mode integration, now more or less working
* integrating async miner workflow
* rocksdb update
* u64 internal difficulty representation, and integration of latest Cuckoo-miner API
* change to cuckoo-miner notify function
* Issue in testing, and if use_async value is None in grin.toml
* making async mode explicit in tests - 2
* fiddle with port numbers for CI
* update tag to ensure cuckoo-miner build doesn't fail on windows
* change the order in which tests are run
* Adding cuckoo-miner into grin as a proper dependency now
* Defaulting to using cuckoo-miner
* Updates to tests to use cuckoo_miner by default, (using cuckoo16)
* addition of configuration file to grin executable, instructions on how it's picked up are in grin.toml
* Starting to add a configuration file, and change some elements of configuration structures to make them more consistent
