Refactor the Keychain to be based on a trait (#1146)

* First pass at restructuring the keychain crate and introducing a Keychain trait
* Parameterized everything that had to. Stuff compiles.
* More stuff compiles, fix most tests
* Big merge, pushing down opening the keychain forced adding factory methods on trait
* Test fixes for pool and servers crate

chain/src/chain.rs

@@ -20,10 +20,10 @@ use std::fs::File;
 use std::sync::{Arc, Mutex, RwLock};
 use std::time::{Duration, Instant};
 
+use core::core::Committed;
 use core::core::hash::{Hash, Hashed};
 use core::core::pmmr::MerkleProof;
 use core::core::target::Difficulty;
-use core::core::Committed;
 use core::core::{Block, BlockHeader, Output, OutputIdentifier, Transaction, TxKernel};
 use core::global;
 use grin_store::Error::NotFoundErr;
@@ -31,8 +31,8 @@ use pipe;
 use store;
 use txhashset;
 use types::*;
-use util::secp::pedersen::{Commitment, RangeProof};
 use util::LOGGER;
+use util::secp::pedersen::{Commitment, RangeProof};
 
 /// Orphan pool size is limited by MAX_ORPHAN_SIZE
 pub const MAX_ORPHAN_SIZE: usize = 200;