Continuing work on script execution + random improvements…

- added params argument to BitcoinSerialization because many subclases use these
- implemented == operator in many classes where it is useful
- improved script parsing
- added TransactionSignature like bitcoinj does that adds a SigHash value to the actual signature

Breaks when using the latest cipher version (dev branch) because of a change in ECDSASigner, will adapt as soon as cipher change is final.