%in% operator not supported

[codeZeilen]

magpie objects currently do not support the %in% operator in that it results in a plain logical instead of another magpie object.

The following results in a magpie object:

maxample("animal") == 5 | maxample("animal") == 6

but this does not:

maxample("animal") %in% c(5, 6)

Still need to check whether this can actually be implemented for a custom class, probably by implementing a custom base::match.