properties files and related resources automatically updated from ggbtrans

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34650 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Fixing null term's toString

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34651 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e