Merged changes from branch "sput" r50:55 back into trunk.

Merged changes from branch "sput" r50:55 back into trunk.

This includes my work of the past few months, most notably a pretty complete rework
of the buffer management and much other GUI code, as well as our new ChatWidget which is
now functional enough to be used. Probably most of the GUI code now looks quite different.

There have also been many cleanups, the obsolete network/ directory is being removed,
and I have started to document some things.