Readd Taglib.Mpeg4.FileParser.UserDataBox property
Readd Taglib.Mpeg4.FileParser.UserDataBox property

The UserDataBox property was renamed to UserDataBoxes and its return type
changed to an array between 2.0.3.7 and 2.0.4.0, resulting in an ABI
breakage. This patch readds the property for backward compatibility.

archrival/taglib-sharp,hwahrmann/taglib-sharp,Clancey/taglib-sharp,punker76/taglib-sharp,mono/taglib-sharp,punker76/taglib-sharp,hwahrmann/taglib-sharp,CamargoR/taglib-sharp,Clancey/taglib-sharp,Clancey/taglib-sharp,archrival/taglib-sharp,CamargoR/taglib-sharp