Fix manipulation functions (push/splice) for mobile devices

Fixed aino issue #315 

This fix handles both push and splice methods when swipe mode is on.  
The problem was partly addressed by satbirjhuti https://github.com/satbirjhuti/galleria/commit/a29ad99fd82ac33e6c1ef995332417a13a90b723, but I believe his solution will still exhibit the same problem when splice is used.