StringElement bugfix (Horizontal text alignment)
StringElement bugfix (Horizontal text alignment)

Bug description:
Multiple StringElements in the same View (some with values set, some without values/only with caption)
Set the alignment of the string element without values to "UITextAlignment.Center"
The alignment of the center elements switches randomly between "left" and "center" at each "ReloadData".

=> reason: if a value is set for a string element, the reuse identifier has been wrong (differed from the reuse identifier which is used to find the element)
newky2k/MonoTouch.Dialog,jstedfast/MonoTouch.Dialog,Milan1992/MonoTouch.Dialog,hisystems/MonoTouch.Dialog,benoitjadinon/MonoTouch.Dialog,migueldeicaza/MonoTouch.Dialog,ClusterReplyBUS/MonoTouch.Dialog,danmiser/MonoTouch.Dialog