Add common chat features

[ajkachnic]

Add some features that are common to this style of messaging application like:

• [x] Markdown Support: Allow users to style their messages with markdown syntax
• [ ] Embeds (or at least clickable links) Use meta tags to render previews of links and images
• [ ] Multi-line message support Self explanatory... could be done with SHIFT + ENTER
• [ ] @ mentions Let users use the @ sign and then a nickname to mention that person and give them a notification
• [ ] Emoji support / emoji picker Self explanitory
• [ ] See who's typing Show the people currently writing a message
• [ ] See who is in the current channel Display the nicknames of everyone in the lobby

[ajkachnic]

Okay I'll update this issue as I make progress on these