fix p2sh with non-standard OP_CHECKMULTISIG from testnet3

  found in testnet3 tx: d3d77d63709e47d9ef58f0b557800115a6b676c6a423012fbb96f45d8fcef830

  two changes along with that fix:
    - change how sign_input_signature takes an optional forced script: binary instead of string format now. (faster, less conversion)
    - drop signatures before passing to sign_input_signature. dropping them inside there still works for backward_compatibility though.
remove BIP_0017: OP_CHECKHASHVERIFY