clear wasn't working as expected. Changed to setInnerHtml("")

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30421 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Check submatrices are proportionnal instead of equal

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30422 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
User-defined icons' image (default image or an image added by the user) is visible on web version too. (#3893)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30423 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e