#371, Link to license broken
#376, Fix tile.clear() calls that got overrun during removal of Prototype.js
#374, Need to bring up new licenses into 2.2 Branch
#336, create OpenLayers.Layer.Graphic to layers created with simple static images
#375, No need to exlude Yahoo.js from singlefile build
git-svn-id: http://svn.openlayers.org/branches/openlayers/2.2@1740 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf