[5.x+]ucar.ma2.StructureData is insufficiently documented

[haileyajohnson]

The documentation on ArrayStructures does not provide and example of how to read and write data to a structure member, e.g. creating a StructureData object, writing with NetcdfFormatWriter.appendStructureData, and reading with Structure.readStructure.

[JohnLCaron]

All deprecated in favor of ucar.array.StructureData in > 5. Which is also insufficiently documented.

Your decision on documenting ver5, I know this will remain Unidata's version for the foreseeable future.