slog-rs logging (#171)

* 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

pool/Cargo.toml

@@ -9,9 +9,9 @@ grin_core = { path = "../core" }
 grin_keychain = { path = "../keychain" }
 grin_store = { path = "../store" }
 grin_p2p = { path = "../p2p" }
+grin_util = { path = "../util" }
 secp256k1zkp = { git = "https://github.com/mimblewimble/rust-secp256k1-zkp" }
 serde = "~1.0.8"
 serde_derive = "~1.0.8"
 time = "^0.1"
 rand = "0.3"
-log = "0.3"

pool/src/lib.rs

@@ -31,7 +31,6 @@ extern crate rand;
 extern crate serde;
 #[macro_use]
 extern crate serde_derive;
-extern crate log;
 extern crate blake2_rfc as blake2;
 extern crate grin_core as core;
 extern crate grin_keychain as keychain;