feature: sidebar hiding on mobile

feature: message actions button (nothing works yet, tho)

README.md

@@ -23,10 +23,16 @@ feature discussions.
 	- [X] avatar uploads
 - [X] chat rooms
 	- [X] chat messages
+	- [ ] chat message actions
+		- [X] '...' button to show actions
+		- [ ] delete message
+		- [ ] reply to message
+		- [ ] copy message link
 	- [ ] @-prefixing of users for notifications/highlighting
 		- [ ] chat input box should auto-complete users for you
 		- [ ] messages to you should be highlighted somehow
 	- [ ] chat message reactions
+	- [X] sidebar on mobile needs to show/hide via a button
 	- [ ] clean up after initial implementation
 		- [X] split the monolithic talk.html up
 	- [ ] chat message processing