nestedtext 4.0.0

A ruby library for the human friendly data format NestedText (https://nestedtext.org/). There is support for decoding a NestedText file or string to Ruby data structures, as well as encoding Ruby objects to a NestedText file or string. Furthermore there is support for serialization and deserialization of custom classes. Support for v3.2.1 of the data format will all official tests passing.