When multipleOfType is true, an output name provider, or the outputNames attribute, is required in order for MBS to know the names of the output files.
+The returned +paths must be relative to the top-level build directory. However, if only a file +name is returned, MBS will automatically add on the directory path relative to +the top-level build directory. The relative path comes from the source file +location. In order to specify that this output file is always in the top-level +build directory, regardless of the source file directory structure, return +"./path".
7.11 Defining an Option Value Handler
You can specify a value handler for an option. You must specify and supply a class that implements the