Add test for calcLength copy constructor
Add test for calcLength copy constructor

CalcLength already implements a copy constructor
(as it takes a CalcDictionary).  Add tests for this.

css-typed-om/typed-om,samthor/typed-om,css-typed-om/typed-om,wilddamon/typed-om,samthor/typed-om,anthony-huang/typed-om,anthony-huang/typed-om,wilddamon/typed-om