[NUCRDBMS-774] Rename MultiMap method
Need core 3.2.14 minimum due to JDK 1.8 change
[maven-release-plugin] prepare release datanucleus-rdbms-3.2.13
[maven-release-plugin] prepare for next development iteration
Merge branch '3.2' of https://github.com/datanucleus/datanucleus-rdbms into 3.2