Room dialog (#905)

* support ToolIcon className and fix label padding

* factor some ExportDialog classes out to Modal

* initial RoomDialog prototype

* change label for another-session button

* remove unused css

* add color comments

* Move the collaboration button to the main menu, add support for mobile

* remove button for creating another session

* add locks

* Fix alignment issue

* Reorder button

* reuse current scene for collab session

* keep collaboration state on restore

Co-authored-by: Jed Fox <git@twopointzero.us>

src/components/ToolButton.tsx

@@ -17,6 +17,7 @@ type ToolButtonBaseProps = {
   showAriaLabel?: boolean;
   visible?: boolean;
   selected?: boolean;
+  className?: string;
 };
 
 type ToolButtonProps =
@@ -43,7 +44,7 @@ export const ToolButton = React.forwardRef(function(
       <button
         className={`ToolIcon_type_button ToolIcon ${sizeCn}${
           props.selected ? " ToolIcon--selected" : ""
-        }`}
+        } ${props.className || ""}`}
         title={props.title}
         aria-label={props["aria-label"]}
         type="button"