This adds a couple of decorators that can be used to
mark functions as needing to be run in the gdb thread
or in the gtk thread.
This found at least one bug.
if you have a gdb that can wrap commands (not yet upstream)
then up/down/frame commands will update the source window
when a selected-frame event is available, we can change
the code to use that instead
This adds the "gui log" command, which pops up a window you can use
for logging.
There are also new "gui" subcommands for sending output to a log
window: gui print, gui output, gui printf, and gui dprintf. These
all work pretty much like their non-gui counterparts, except that the
output goes to the log window.
If you have more than one log window you can specify which one to use
with an "@", like gui print @1 value
This adds the "info windows" and "delete window" commands.
"info windows" unfortunately overlaps with the TUI's "info win".
So maybe we should rename this one.
This also adds a new "toplevel" component that knows how to track
windows.
