* Add compare method to COLOR4D object.
* Add unit test to validate COLOR4D comparison method.
* Add missing color test in text attribute comparison method.
* Add unit test for text attribute object.
* Remove unnecessary headers from text attribute header.
* Move text attribute code into separate source file.
Fixes#13062Fixes#13056Fixes#13057
However, DXF and HPGL is not perfect, but OTOH this is not an usual format for schematic.
PS format is not tested for now.