Suppress unused parameter warning in wxRichTextCtrl code.

The entire event handler should arguably be removed entirely if it's unused,
but for now just avoid the warning.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78286 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Undo the change of the number of items in dataview sample.

Increasing it to 10000000 in r77905 brought both the native GTK (see #16741)
and OSX (see #16740) wxDataViewCtrl implementation to their knees, so don't do
this.

This is, of course, just hiding the real bug, but still better than not
allowing people to run the sample at all.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78287 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Add GetDefaultType() to all standard wxDataViewRenderer-derived classes.

This makes it possible to refer to the associated wxVariant types without hard
coding the string constants, i.e. instead of writing "string" (error prone as
typos are not detected) it is now possible to write wxDataViewTextRenderer::
GetDefaultType().

This will also make it simpler to write generic (in C++ templates sense) code
using renderers.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78288 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Use helper functions for {app,prep}ending wxDataViewCtrl columns.

Make the code more maintainable by using helper functions instead of
duplicating the same logic a dozen times for each of appending and prepending.

This is just a refactoring, no changes in behaviour.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78289 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Centre text vertically in wxDataViewCtrl by default in generic version.

This was already the case in the native GTK (possibly unintentionally) and OS
X (because vertical alignment is not supported at all there) versions, but in
the generic version using the default wxALIGN_NOT alignment when calling
wxDataViewCtrl::AppendXXXColumn() methods resulted in top-aligned text which
looked ugly (this could be seen on the second page of the dataview sample for
example).

Fix this by handling wxALIGN_NOT as wxDVR_DEFAULT_ALIGNMENT in these functions
to do the right thing by default.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78290 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775