DateTime doesn't serialize with correct timezone #45
Description
It seems JST time is serialized as UTC.
$sbt console
scala> import org.joda.time._
import org.joda.time._
scala> import codecheck.github.models._
import codecheck.github.models._
scala> val d = DateTime.now
d: org.joda.time.DateTime = 2015-05-25T19:47:03.309+09:00
scala> val input = IssueListOption(since=Some(d))
input: codecheck.github.models.IssueListOption = IssueListOption(assigned,open,List(),created,desc,Some(2015-05-25T19:47:03.309+09:00))
scala> input.q
res1: String = ?filter=assigned&state=open&sort=created&direction=desc&since=2015-05-25T19:47:03Z