Various ARIA a11y fixes.

Notate RightPanel tabs.
Shorten Screen Reader queues.
Make AccessibleTooltipButton screen reader friendly
Flatten DOM for Sticker button using React Fragments

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/views/groups/GroupRoomInfo.js

@@ -214,7 +214,7 @@ module.exports = createReactClass({
 
         const groupRoomName = this.state.groupRoom.displayname;
         return (
-            <div className="mx_MemberInfo">
+            <div className="mx_MemberInfo" role="tabpanel">
                 <GeminiScrollbarWrapper autoshow={true}>
                     <AccessibleButton className="mx_MemberInfo_cancel" onClick={this._onCancel}>
                         <img src={require("../../../../res/img/cancel.svg")} width="18" height="18" className="mx_filterFlipColor" />