* minor cleanup - unused imports
* cleanup build warnings - unused vars
* make structs pub to get rid of the private_in_public lint warning
* missing docs on RangeProof
* add missing docs to store delete function
* cleaned up deprecation warning -
tokio_core -> tokio_io
complete() -> send()
* 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