* change gas cost for contract creating txs
* invalidate signature with s value greater than secp256k1 N / 2
* OOG contract creation if not enough gas to store code
* new difficulty adjustment algorithm
* new DELEGATECALL op code
* Add fixes to parsing and converting of fields in tx tests
* Correct logic in tx tests; validation of fields and correct
logic for when RLP decoding works/fails and when this is
expected or not
* Rename files for consistency
* Add block tests wrapper to run block tests with go test
* Include tests which now has consistent HEX encodings
* Comment out two failing tests: "
"TransactionWithHihghNonce" due to wrong nonce size
"TransactionWithSvalueHigh" due to wrong ECDSA s range
* Cleanup conversion functions and fix expected encodings for
tests validation fields
* Add initial go wrapping for TransactionTests with some tests
disabled in lieu of consistent HEX encodings and a few other
pending bugfixes
* TODO: Consider better way of perhaps modelling each test in
the JSON files as a single Go test, instead of one Go test per
JSON file
