Make FTP an experimental feature

package.json

@@ -90,7 +90,7 @@
         "c9.ide.imgeditor": "#66a9733dc1",
         "c9.ide.immediate": "#29fd6d3f51",
         "c9.ide.installer": "#0fde9f0067",
-        "c9.ide.mount": "#3e017a3324",
+        "c9.ide.mount": "#4606e039dc",
         "c9.ide.navigate": "#c191d9b92f",
         "c9.ide.newresource": "#981a408a7b",
         "c9.ide.openfiles": "#7fa4a97fed",