Doxygen cleanup
Fix mdb_page_split - nested split

If updating a page's separator triggers a split in its parent,
we may have missed adjusting the parent's cursor position.
Include <netinet/in.h> for Solaris 8

Needed for <resolv.h>, which is needed for BYTE_ORDER.
ITS#7589 mdb_cursor_put(): Update ovpage nodesize.

Update the nodesize when overwriting an overflow page.
As before, do not attempt to shrink the page.