wxFileDialog::SetWildcard() and case sensitivity

[Robert Roebling]

> Also, some people may want to treat their extensions case-sensitively (.c
> vs .C for example) so we should probably have an option for this, although
> I'd be for treating them case-insensitively, for consistency with the other
> platforms, by default.

Isn't OS X case sensitive as well? Also, people using a GTK+ app
will expect its file open dialog to be case sensitive, so changing
this might not do what people want it to do.

  Robert