Make sure autosave only starts in app mode

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37180 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Do not replace "" by "" in image manager

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37181 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e