#4457 - GeoLine and GeoSegment have opacity value

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35355 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] Change for #4455

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35356 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#4457 - moved line opacity related methods to GeoElementND, GeoPolygon has line opacity

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35357 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e