{{each}} itemView option

Allows ``itemView`` option into the each/collection helper. If itemView
exists and there is a controller container, then it will attempt to
resolve the view via the container.

Chose the name ``itemView`` because its API is similar to 
``itemController``.  It only takes a name, no namespace/type required.

The reason for this is so ``{{each`` can find its item view via the 
resolver.