Rename utils -> tools.
Add icmp, an iterator comparison relational.
Add hybrid level-compressed / node-compressed PATRICIA trees, and associated unit tests.
Add list and tuple as importable names to the tools module, using the optimized blist implementations if available.
Formatting fix.
Re-write PATRICIA trees to have a variable-length binary string value type, opposed to the hash256 which was used before.
Eliminate masking class names - TestPatriciaLinkSerialization test suite is now executed.