integration tests for scripthash transcations
Merge pull request #162 from sidazhang/master

Adding integration tests
Fixes incorrect PubKey hex constant
Changes sequence number to an actual Number
Changes fakeTxHash to actual hex
Serialize now returns a buffer
Adds Buffer extensions
Changes internal serialization to use Buffers instead
Adds performance notes
Corrects endianness comments
Renames hashTransactionForSignature to hashForSignature