Bunch of soldiers running from the top middle of the screen into ranks.
Added "z" order sorting for batch and single sprite processing.
+++ BUG: in batch mode only the first soldier appears top/center, all others appear increasingly far down the screen... I've been unable to debug this problem so far (advice welcomed!).  NOTE: reversing soldier positions so they appear bottom center and march up the screen shows the same effect reversed leading me to believe it's in the shader... especially as the single sprite processing version works properly in both modes.