Allow a:x+y+z=0 in CAS

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36208 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
allow marble in CAS for x+y+z=0

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36209 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
More language selection simplifications.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36210 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e