Terrain updates not handled in delta time

[John Westhoff]

Bending/src/main/java/com/johnwesthoff/bending/ClientUI.java

Lines 518 to 522 in db33e0e

 try { 
     sess.world.ground.handleWater(); 
 } catch (Exception e) { 
     e.printStackTrace(); 
 } 

This code should be in the delta time loop - right now clients can easily fall behind on terrain movements. This can probably be done before #50.