The `patricia_trie` crate is generic over the hasher (by way of HashDB) and node encoding scheme. Adds a new `patricia_trie_ethereum` crate with concrete impls for Keccak/RLP.
* Update `add_license` script
* run script
* add `remove duplicate lines script` and run it
* Revert changes `English spaces`
* strip whitespaces
* Revert `GPL` in files with `apache/mit license`
* don't append `gpl license` in files with other lic
* Don't append `gpl header` in files with other lic.
* re-ran script
* include c and cpp files too
* remove duplicate header
* rebase nit
* WIP
* Replace Rlp with UntrustedRlp in views, explicity unwrap with expect
First pass to get it to compile. Need to figure out whether to do this or to propogate Errors upstream, which would require many more changes to dependent code. If we do this way we are assuming that the views are always used in a context where the rlp is trusted to be valid e.g. when reading from our own DB. So need to fid out whether views are used with data received from an untrusted (e.g. extrernal peer).
* Remove original Rlp impl, rename UntrustedRlp -> Rlp
* Create rlp views with view! macro to record debug info
Views are assumed to be over valid rlp, so if there is a decoding error we record where the view was created in the first place and report it in the expect
* Use $crate in view! macro to avoid import, fix tests
* Expect valid rlp in decode functions for now
* Replace spaces with tabs in new file
* Add doc tests for creating views with macro
* Update rlp docs to reflect removing of UntrustedRlp
* Replace UntrustedRlp usages in private-tx merge
* 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
