Now a cell can either have a "fixed" size or it can have
an "aligned" starting point or both. "fixed" size cells take
no space when they are invisible.
It's a better test case if the scaffolding only displays the rows from top
to bottom and doesnt line up the cells from left to right (because it shows
that height-for-width still works with vertically oriented areas).
CellAreaScaffold now also reflects how cell_area should be
passed to gtk_cell_area_activate() and gtk_cell_area_event()
and how the background area for gtk_cell_area_renderer() should
be created.
- Added gtk_cell_area_aligned_cell_area() to get the aligned
internal area use by a cell (for focus painting and for
event areas).
- Provide the event area in "editing-started" signal
- Fire "remove-editable" when editing is canceled by the user,
an implementing layouting widget need only catch "editing-started"
and "remove-editable" now.
- CellAreaScaffold/testcellarea now edit textrenderers.
Added concept of "Focus Siblings" to GtkCellArea so that some
static text/icon may be included in the focus/click area of
an activatable or editable cell, implemented focus drawing
as well, updated testcellarea to reflect the changes.
- Fixed focus driving in GtkCellArea with refined apis
- Added gtk_cell_area_activate() to be called when the area has focus
(to activate or start editing the focused cell)
- Added support for this in cellareascaffold
- testcellarea now watches the "toggled" signal for a toggle renderer
and updates the model state accordingly, this currently works with
keyboard navigation, however focus is still not painted on cells.
