rlp serialization refactor (#4873)

* fixed naming of rlp modules

* RlpStream cleanup

* appending short rlp lists (0...55 bytes) is 25% faster

* RlpStream does not use bytes module, nor trait Stream

* removed unused code from rlp module

* compiling ethcore-util with new rlp serialization

* compiling parity with new rlp serialization

* fixed compiling ethcore-light with new rlp serialization

* fixed compiling ethsync with new rlp serialization

* removed redundant comment, print

* removed redundant double-space

* replace usage of WriteBytesExt with ByteOrder

ethcore/light/src/net/mod.rs

@@ -24,7 +24,7 @@ use ethcore::receipt::Receipt;
 
 use io::TimerToken;
 use network::{NetworkProtocolHandler, NetworkContext, PeerId};
-use rlp::{RlpStream, Stream, UntrustedRlp, View};
+use rlp::{RlpStream, UntrustedRlp, View};
 use util::hash::H256;
 use util::{Bytes, DBValue, Mutex, RwLock, U256};
 use time::{Duration, SteadyTime};