Patch set: improve window titles

OK: here is the complete set:


    Patch: dpi-downloads_window_titles

        Nice window  titles for the  Downloads DPI (which is  the only
        DPI that creates windows).

            http://starurchin.org/dillo/patch/dpi-downloads_window_titles.html


    Patch: dillo_window_titles

        Nice window titles for Dillo.

            http://starurchin.org/dillo/patch/dillo_window_titles.html


    Patch: dillo_window_titles_parameterise

        Make all  the window titles  parameters of the  functions that
        create them instad of hardwiring them.

        Rename some variables (some titles  were named "msg") and swap
        two function parameters for consistency.

        Titles may be NULL or empty,  in which case we default to what
        we had before.

        NB: choice5  also handles a  NULL msg,  since msg may  be read
        from a  DPIP tag in  a "dialog"  DPI command and  this returns
        NULL if the tag does not contain the key "msg".


    Patch: dpip-dialog_titles

        Make all  DPIs that use  the "dialog" command supply  a title.
        (There is  one instance of this  in the hello DPI  and many in
        the https DPI.)

            http://starurchin.org/dillo/patch/dpip-dialog_titles.html


Please comment.   There is  nothing complicated  or disruptive  here -
just  some  minor  polishing  of  the  GUI  and  the  code  base.   No
functionality is changed.

I will push after the weekend if noone objects.

(It's nice to be hacking on Dillo again!)

Regards,

Jeremy Henty