Test-driven development!
Need klen on the key.
Fleshed out the expiration function.
Getting back to the mayo metaphor.

- Values are not returned if they are expired.
- Changed ol_set_expiration to ol_spoil. Lol.
Expiration works properly for keys that don't have it set.
Added spoiling to the AOL test. Currently does not read.
Time so fucked right now.

Turns out serialization of timestamps is stupid-hard. I'll probably end
up switching the time_t object to a struct tm object.