#3899 SliderPanelW for the web (no anim step and speed panels yet)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30494 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3857: IE does not show rectangle on hold, removed experimental code

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@30495 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e