* Construct unpacking functions for byte format up front to save time
wasted on parsing format string every iteration.
* Store length ahead of time as the overhead adds up.
* Reduce object attribute lookups in hash functions.
* Clean up lib pkg API changes. Unit test new "public" API members.
Underscore prefix for internal hash module funcs. Make bytes.fromhex a
public function.
* Document recent performance findings.
It turns out clients pass 0.10 instead of 1.0 as the protocol version.
Distinguish some handlers for 1.0 and 1.1 protocols.
Log protocol version request
Add tests of new library function
