fix printform for undefined lines

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37571 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Fix for #4714

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37572 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
5.0.30.0

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37573 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
fix for NSolve[If[-4<=x<=5,x-1,If[5<x<=7,2x-7]]=-4]

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37574 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e