registers a toolbar such that it can be linked to editors
function(scope){
			if(!scope) throw('textAngular Error: A toolbar requires a scope');
			if(!scope.name || scope.name === '') throw('textAngular Error: A toolbar requires a name');
			if(toolbars[scope.name]) throw('textAngular Error: A toolbar with name "' + scope.name + '" already exists');
			toolbars[scope.name] = scope;
			angular.forEach(editors, function(_editor){
				_editor._registerToolbar(scope);
			});
		}