Bringo/GMGridView — comment on commit 23c4698332871d8e259330904063543da562e36e
File:  line 0
By Bringo:

Extended the sortingDelegate with two more optional delegate methods:

`+- (BOOL)GMGridView:(GMGridView *)gridView shouldAllowMovingCell:(GMGridViewCell *)view atIndex:(NSInteger)index;` is called when a move is about to start. If this method returns `NO`, the move won't take place.

`+- (BOOL)GMGridView:(GMGridView *)gridView shouldAllowMovingCell:(GMGridViewCell *)view toIndex:(NSInteger)index;` is called when an item is moved to a new position in the grid. If this method returns `NO`, the insertion won't take place.