Avoid quotes around username

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34334 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Basic fix for #4354

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34335 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3392 Editable cell

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34336 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e