cache tx binary hash

This gets called *a lot*. To my surprise there is actually measurable
improvement in block store time with this.
let's not recalculate hashes for objects fetched from db

We have check consistency for that.
Comparison "blk.hash == blk.recalc_block_hash" in consistency check
would even suggest that blk.hash is expected to be fetched from the db
fix some old typo preventing script cache
cleanup script naming in txout