Expose service.copy() for the clipboard plugin.

lib/roles/device/plugins/service.js

@@ -270,6 +270,12 @@ module.exports = syrup.serial()
         })
     }
 
+    plugin.copy = function() {
+      // @TODO Not sure how to force the device to copy the current selection
+      // yet.
+      return plugin.getClipboard()
+    }
+
     plugin.wake = function() {
       return runAgentCommand(
         apk.wire.MessageType.DO_WAKE