Fix problem where scroller height kept getting incremented when dragging items down in list due to this.portSize not getting updated when pageHeight was recomputed.

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@palm.com)
Remove dead code, switch to using enyo.dom.calcNodePosition instead of List's implementation

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@palm.com)
Update placeholder position while autoscrolling to make for smoother reorder
Factor out the reposition placeholder code since it's used in three places now
Get rid of more parseInt code by using getBounds method instead
Avoid crash at end of pinned mode reorder by adjusting when we clear state

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@palm.com)