Allow duplication of GeoAlignableTransforms for alignable elements

Change to try and address Issue #116. The same GeoAlignableTransform was being used for multiple elements to be aligned because the de-duplication already found a transformation with that name, so it returned that instead of creating a new one.

@rbianchi and @jojungge may want to comment on whether they are happy with this fix or it should be addressed in a different way.