improvements and bug fixes

improvements
-  added methos
- Navigation.next();
   - Navigation.prev();
   - Navigation.keepPos();

bug fixes
- keep panel position after window resized
- ensure that the final panel
won't disappear when the window is resized. (**still not working on
safari and ie9+**)
improvements and bug fixes

improvements
-  added methos
- Navigation.next();
   - Navigation.prev();
   - Navigation.keepPos();

bug fixes
- keep panel position after window resized
- ensure that the final panel
won't disappear when the window is resized. (**still not working on
safari and ie9+**)