add redrawItemAtIndex helper
make datasource and delegate weak
add contextMenuForRightClickAtIndex delegate
Convert contextMenuForRightClickAtIndex to IBOutlet
Introduce contextMenuForRightClickAtIndex
Merge branch 'master' of github.com:i386/CNGridView
rename rightClickContextMenu to itemContextMenu and update example
update popup menu variable
switch from NSUInteger to NSIndexSet for right click menu
context menu for item now respects item selection
deselect items if click is not on an item
do not show context menu when right click is not on a item
Add shift and command modifier selection. Drag to select functionality can now be enabled/disabled.
Fix crash where notification observers were not removed on dealloc
add visibleIndexes method
If right click is not on a selected item, deselect all items and select the clicked item
set needs display on visible item rather than readding the item view
representedObject for CNGridViewItem
remove debug log message
Revert "set needs display on visible item rather than readding the item view"

This reverts commit 58750b2d8a8ac2a05f219dc4ce92eef1266fd7b9.