Client

Quick fixes:

-[x] Bind Enter to send button -[x] Prohibit users from sending empty messages

Planned fixes:

-[ ] Not quitting properly on Windows

Planned features:

-[ ] Signup -[ ] Send pictures -[ ] Read/unread

Future features:

-[ ] Contacts -[ ] Edit sent messages

Server

Planned fixes:

-[ ] msg_scraper disconnects randomly -[ ] make request_handler robuster, e.g. handling non-standard incoming requests