Don't relayout scrollpanels every time something changes

Gemini's habit of reflowing everything everytime anything changes at all makes
for an unresponsive app. Turn it off everywhere we use gemini.

src/components/structures/ScrollPanel.js

@@ -540,6 +540,7 @@ module.exports = React.createClass({
         // it's not obvious why we have a separate div and ol anyway.
         return (<GeminiScrollbar autoshow={true} ref="geminiPanel"
                 onScroll={this.onScroll} onResize={this.onResize}
+                relayoutOnUpdate={false}
                 className={this.props.className} style={this.props.style}>
                     <div className="mx_RoomView_messageListWrapper">
                         <ol ref="itemlist" className="mx_RoomView_MessageList" aria-live="polite">