Ternary for streaming based on Accept HTTP header.

( route, /^/status/ ) ( accept, "text/html" ) ( PRE ) ( player_status ) () () (accept, "text/plain") (undefined, {headers: { "Content-Type": "text/plain"}}) ( player_status ) () ()

Notes / TODOs:

• Does not account for q-factor (not sure that's possible in fab).
• Need to implement RegExp matching to make more useful.