Adding support for closure compiler and some documentation

in the README about how to use it.


git-svn-id: http://svn.openlayers.org/trunk/openlayers@11448 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

tools/closure_ws.py

@@ -22,5 +22,7 @@ def minimize(code):
     response = conn.getresponse()
     data = response.read()
     conn.close()
-    print "%.3f seconds to compile", time.time() - t 
+    if data.startswith("Error"):
+        raise Exception(data)
+    print "%.3f seconds to compile" % (time.time() - t) 
     return data