v0.4.0

API changes:

• adding findFirst() to Sets, for unboxing singleton sets
• adding factory methods for binary relation type
• defaulting to JDK's Optional

Other changes:

• major changes in PersistentTrieSetMultimap
• new base classes for code sharing between multi-maps
• preliminary serialisation support (unstable and incomplete)

v0.3.2

Bugfix release. Adds a missing equals implementation of the multi-map's hash collision node.

v0.3.1

v.0.3.1 was released with a semantically wrong version number is therefore obsolete.
It was re-released as v0.4.0.

v0.3.0

• restructuring of APIs: data types such as Set now have nested Set.Immutable and Set.Transient interfaces.
• preliminary support of set multi-map data type and binary relations.

v0.2.1

Re-release under BSD 2-Clause License open source license.