Fixed: subviews in cib did not receive view(Will/Did)MoveToSuperview:

In Cocoa, viewWillMoveToSuperview: and viewDidMoveToSuperview: are called when views are instantiated from code or from a nib.

Previously in Cappuccino, when a view was instantiated from a cib, the _subviews of the view were directly set from the decoded subview array. This short-circuited all of the normal notifications a view receives when added to a superview, including viewWillMoveToSuperview: and viewDidMoveToSuperview:. As a result, some views that override these methods, such as CPSearchField, were not set up correctly when instantiated from a cib.

With this commit, subviews instantiated from a cib are manually added to their superview, thus ensuring they go through the same cycle as views instantiated from code, and ensuring that viewWillMoveToSuperview: and viewDidMoveToSuperview: are called.

Closes #1699