Many fixes, along with extensive cleanups and refactoring of code to

Many fixes, along with extensive cleanups and refactoring of code to

Fri Jun  6 16:25:44 2003  Owen Taylor  <otaylor@redhat.com>

        * gtk/gtkviewport.c: Many fixes, along with extensive cleanups and
        refactoring of code to reduce duplication; fixes include:

        - gtk_viewport_realize(): Position the window correct from adjustment
        values. (#110737, Michael Natterer)

        - Remove some division-by-zero checks in places where there is no
        longer division. (#110737)

        - gtk_viewport_class_init: Make the hadjustment/vadjustment properties
        G_PARAM_CONSTRUCT, so that there will always be adjustments, even
        if gtk_viewport_new isn't used (#101135, Thomas Leonard).

        - Switch over to encapsulated lazy-creation for hadjustment/
        vadjustment; even with the CONSTRUCT property, we need this after
        destroy.

        - When updating the adjustment, immediate set their values to
        match the the current range of the viewport, and update the
        viewport position to match the value of the new adjustments.
        (Part of #1165