Remove unnecessary comments; as long as the variables
and functions have a clear name, they are self documenting,
so they don't need additional comments.
When getCurveSet() is called on an unsupported entity, it runs into a
NameError exception because elts is not defined. Instead print a message
and return gracefully.
This is in line with overall behaviour of the importer: Ignore
unsupported elements instead of thowing errors.