* added global slog instance, changed all logging macro formats to include logger instance
* adding configuration to logging, allowing for multiple log outputs
* updates to test, changes to build docs
* rustfmt
* moving logging functions into util crate
* 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()
