Fix for #62

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@27343 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[cas] parametric - lhs can be any label

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@27344 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] Remove error for obj[int] + some bug fixes + experimental faster code for Groebner basis 

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@27345 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
reverting r27343 #62 (breaks lots of CAS tests)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@27346 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e