This release adds Scala 2.12 support (#16) and includes a couple of sets of additions and some API clean-up.
You can now use Scala's Map, Set, or Vector collection types as labels without having to write your own Layout instances describing how to serialize and deserialize them (#17). If you need Layout instances for other collection types, you can define your own on the model of these three instances.
There are also new collectLabels and collectLabelsF methods on TreeOps, and collectLeafLabels and collectLeafLabelsF methods on FullBinaryTreeOps (#15 and #19). These methods make it more convenient to collect the set of labels for a tree (or a set of values resulting from a transformation of the labels).
There are also several breaking changes in the signatures of methods on FullBinaryTree and FullBinaryTreeOps. The first function argument to all fold and reduce methods now takes the label and then the children, and all of these methods now take both function arguments in a single parameter list. See #19 for the motivation for these changes.