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
Removes redundant convert functions
Adds performance notes
Corrects endianness comments
Renames variables to be more verbose
Transaction.deserialize no longer mutates input
Merge pull request #170 from dcousens/bufferx

BufferExt and Transaction serialization to use Buffers
move fixture sync script into fixtures folder

Also fixes require paths & dev dependency