Added buffers for each channel.

Created by: ca1ek

Each channel gets it's own buffer.

1. Message is received
2. Message is put into an according buffer
3. If the channel is focused on, the buffer is printed every turn of the 'stdout loop, if the channel isn't focused, the buffer will be printed when you switch to it.

Once, I had a problem with going /back trough channels, I will look into that. It's supposed to loop over from the first to the last when you try that, but it didn't succeed. No crashes.