Slider refactoring part 1

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33417 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Styling comboboxes

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33418 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Slider refactoring part 2

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33419 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Slider refactoring part 3

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33420 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e