Remove all top/bottom margins from buttons and apply to GridFieldButtonRow component. Ensure that all buttons are added to a suitable GridFieldButtonRow in ModelAdmin, SecurityAdmin and Group.
Cleanup of framework's use of @package and @subpackage labels and additional of labels for classes missing packages.
Moved all GridField related components to the one name.
Countless spelling fixes, grammar for other comments.
Link ClassName references in file headers.
