ZODB: based on 5.3.0-5-gcb928231e + y/rawext patch
zodbtools: with not-yet-in-master format stabilization + rawext

The main reson why generated files change a lot is because of this ZODB
commit:

https://github.com/zopefoundation/ZODB/commit/be5a9d54

where pickle protocol used to save data under python2 changed from 1 to 2.