Paper and ToolbarTitle should allow regular HTML attributes.

material-ui/material-ui.d.ts

@@ -654,7 +654,7 @@ declare namespace __MaterialUI {
     export class Overlay extends React.Component<OverlayProps, {}> {
     }
 
-    interface PaperProps extends React.Props<Paper> {
+    interface PaperProps extends React.HTMLAttributesBase<Paper> {
         circle?: boolean;
         rounded?: boolean;
         transitionEnabled?: boolean;
@@ -1256,7 +1256,7 @@ declare namespace __MaterialUI {
         export class ToolbarSeparator extends React.Component<ToolbarSeparatorProps, {}> {
         }
 
-        interface ToolbarTitleProps extends React.Props<ToolbarTitle> {
+        interface ToolbarTitleProps extends React.HTMLAttributesBase<ToolbarTitle> {
            text?: string;
         }
         export class ToolbarTitle extends React.Component<ToolbarTitleProps, {}> {