helpers for Config.time and Config.uri
Merge pull request #22 from heroku/time-and-uri

helpers for Config.time and Config.uri

Adds Config.time and Config.uri type casters.

Config.time tries Time.parse, then on rescue falls back to our "split the string on dashes and splat into Time.utc" so you can set a time as '2012' and it will parse to Jan 1st, 2012 in UTC.

Also replaced some ternary operators with a simple && clauses.