Set Max Width on Desktop

[jimmcgaw]

Right now the chat messages will expand to fill the entire screen. Actually, they're set to 80% of the screen width, but on wider monitors, that might be quite large. This is a potential usability issue with longer messages; really long lines of characters that wrap onto multiple lines are difficult to read when long. The Internet has varying opinions but around 75 characters per line might be a good starting point.