Revert "Revert "Export interfaces on the JAR  - use eclipse -> right click on the project explorer, export, java, JAR. Select the following classes: NavigationItem, OnDataChangedListener, Discount, Store, WebServiceResultHandler  - you can use this JAR to create extensions, with your module can:  	- create navigation items (using NavigationItem interface) 	- subscribe to listening data changes to stores and discounts (using OnDataChangedListener interface) 	- get responses from the web service (using WebServiceResultHandler interface)  - name the JAR air-interfaces and press finish  - on this commit you can find it in the "extras" folder ""

This reverts commit 1ca5f66906d9e9b351c3c34f5960c0ff86fc1dfd.