Add commands

Add the feature to process simple commands (every message that starts with '/')
Examples:
/help
Set font size in pixel
/set font size 13
Set font color as well known colors, hexcode or rgb/rgba value
/set font color red OR /set font color #00FFFF OR /set font color 0 0 0 1
Set background color, see font color
/set background color....
etc.

I'll do this one instead of emoticons

I've added some support, so far just the /me command, but soon other commands