update version to 3.0 snapshot of g-d-m
Merge branch '2.3.x' of github.com:grails/grails-core into 2.3.x
GRAILS-11099 - improve binding to inherited persistent properties

Functional test: https://github.com/grails/grails-functional-tests/commit/344d51a10746c72ed3b67ae4b294c3340d3e2580
Merge branch '2.3.x'