* 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
* changes to use blake2 for cuckoo seed generation
* updating tests to blake 2
* 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 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)
* Refactoring to allow for different miner implementations. Added conditional support for compiling and loading the cuckoo-miner plugin project.
* Small changes to experimentally integrate with cuckoo-miner and compatibility with latest version of cuckoo-miner.
* Turning off inclusion of cuckoo_miner by default
* Disabling simulate_parallel_mining test for now
* core: cleanup slicing impls for Hash
* core: clean up Readable trait, implement Readable/Writeable for various integers
* core: change Hash debug output to hex
* core: correct warnings in all modules