txscript: Optimze typeOfScript pay-to-pubkey
txscript: Optimze typeOfScript pay-to-pubkey

This continues the process of converting the typeOfScript function to
use a combination of raw script analysis and the new tokenizer instead
of the face less efficient parsed opcodes, with the intent of
significantly optimizing the function.

In particular, it converts the detection of pay-to-pubkey scripts to use
raw script analysis.

tb00/btcd,davecgh/btcd,davecgh/btcd,ltcsuite/ltcd,btcsuite/btcd,btcsuite/btcd,ltcsuite/ltcd,tb00/btcd