Replace MapDB with H2 MVStore

v0.6.0

v0.6.0 fix

Scala 2.13 support

This release runs on Scala 2.13 in preparation for Scala 3. At this point in time though there does not seem to be good mock object support on Scala 3.

JPickle for Java Journal

v0.5.0

creating tag for v0.5.0