* WIP: some convenience (self.param=() for Ruby PCell impl), a bug fix (crash on call of pcell_parameter on wrong cell), update of tests
* Implemented solution for #1079 (refresh calls coerce_parameters)
* Basic.CIRCLE modified such that coerce_parameters_impl also catches the case of a programmatic change of actual_radius and this function will update radius and the handle accordingly
* Modified Basic PCells such that they work with coerce_parameters also if generated programmatically
* Added tests
