Change the "user_saved" member of a capture_file structure to

Change the "user_saved" member of a capture_file structure to
"unsaved_changes", and have it be TRUE iff changes have been made to the
file since it was read - *not* if it's a temporary file from a live
capture.

Check the "is_tempfile" member, and the "unsaved_changes" member, when
appropriate.

Just have a set_toolbar_for_capture_file() routine that updates the
"save", "close", and "reload" toolbar as appropriate, given a
capture_file structure - absorb the function of
set_toolbar_for_unsaved_capture_file() into it.

svn path=/trunk/; revision=42721