Selection should be set to -1 if all pages are deleted, or the next

Selection should be set to -1 if all pages are deleted, or the next
insertion will try to set the selection to 1.
Fixed lack of initial controller resize when first page is added,
though I think the listctrl should probably always have a decent initial
height even when empty.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@39210 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775