ui/gtk/main_titlebar.c, with set_titlebar_for_capture_file() for either
no capture file or an opened capture file and
set_titlebar_for_capture_in_progress() for an in-progress capture.
svn path=/trunk/; revision=48683
ui/gtk/gui_utils.c into ui/gtk/main_titlebar.c, and the declaration of
one of them out of ui/ui_util.h into ui/gtk/main_titlebar.h, and rename
them to clarify that they work on the window name and titlebar.
svn path=/trunk/; revision=43041