Cache canvas size to make sync file loading work

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34145 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3392 Step input added to Points tab

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34146 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e