added a function sendMessage
added a function sendMessage

This function is very simple. It sends a chat message, clears the input box, and waits 3 seconds before letting the user send another chat message.

Unfortunately, there are some problems between this and the server that are currently being worked on.

Cardshifter/HTML-Client,SirPython/HTML-Client,Cardshifter/HTML-Client,SirPython/HTML-Client