Show "corner navs" on demand

[mindeffects]

Hi Jason,
it would be a handy thing to have a property which controls whether the "corner navs" shall be shown or not. That would mean that "first" and "prev" would be shown on page "1" and "next" and "last" on page "n". Those elements could get the class "inactive" which everybody can style the way it is needed (like: "pointer-events: none; opacity: 0.5;" ).

This would make the overall pagination a little more "relaxed", since the corner elements would be constantly visible.

Cheers
Oliver

P.S.: This issue was already brought up some time ago and there is also a PR for that:
#23