TexturePaint/GPaint typecast fix

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36794 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
removed "flex" (css) for the header. use Popup for "signOut-optionsPanel".

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36795 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[web] euclidian view on long touch creates context menu

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36796 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e