toolkey, toolDefinition are required. If group is not specified will pick the last group, if index isnt defined will append to group
function(toolKey, toolDefinition, group, index){
			taRegisterTool(toolKey, toolDefinition);
			angular.forEach(toolbars, function(toolbarScope){
				toolbarScope.addTool(toolKey, toolDefinition, group, index);
			});
		}