Add Next/Previous Award/Player navigation elements

[pdinklag]

On player and award pages, add navigation elements to the next and previous award (lexicographically) or player (in what order?), respectively, to make browsing a little easier without having to go back to the main page.

[braydofficial]

I'd say the order should be sorted from the player with

• either the most points
• or the most play time

so that it'll be sorted from the most active players to the less active players