Nice suggestion: allow "change layers" on PCells which support a single "layer" parameter #73
Description
The suggestion was derived from this discussion in the forum: https://www.klayout.de/forum/comments.php?DiscussionID=1023&page=1#Comment_4698.
User expectation was to be able to change the layer of a Basic.TEXT PCell using "change layer". Since such a PCell is a cell instance, not a shape, this operation is not supported. But intuitively, one would expect that PCells which generate single layer layouts, support the "change layer" semantics as well.
Implementing "change layer" for PCell instances which provide a single (and layer-typed) parameter named "layer" is probably a low hanging fruit.
