Don't inject CAS (and any other scripts) twice, if more applets in one page. Still not solves CAS problem of renderGGBElement on second rendering

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30445 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
typo

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30446 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e