Add functionality to filter based on tile dimensions

[emc5ud]

What I'd like to do:

chipped_rf.filter(rf_dimensions('B4') == (256, 256))

What I had to do instead:

chipped_rf.filter(rf_dimensions('B4).cols == 256).filter(rf_dimensions('B4').rows == 256)

[metasim]

This looks more like generic tuple predicates. Might require method injection onto Python column class.