Fix missing "Expand" links on board pages

Since post preview detected .summary, short threads on the board page
couldn't be expanded. Changed 'expand' to always appear on board pages.

Speaking of, "expand" is a misnomer. It's really just a link to the full thread.
Fix relative date stale delay

As per ihavenoface/4chan-x#179
Use if-block in relative-dates updater
Refactor relative-dates code into proper files

Also fix some uncaught bugs, embarassing.

visibilitystatechange -> visibilitychange
Change updater window.focus -> doc.visibilitychange

Apparently window.focus doesn't fire for simple tab switches
Fix message hiding implementation

Need to get bacon.js online still
Timestamp successful build messages

So you can be sure your last changes really got picked up by `watch`
Defer to coke.co's builtin functions

Good ol' perl slurp and spit
Make Cokefile timing more sexy

If only my netbook wasn't so slow:

Commonjsification  : 4486ms
Reparse JS         : 361ms
Coco compilation   : 2908ms
Stylus compilation : 703ms
AST->JS            : 560ms
Total build time   : 5071ms