job and work query functionality added

job?query
  1. added 'date_start' and 'date_end' options
     - can use together or separately
     - uses job.Info.SubmitTime
     - must be ISO 8601 complaint date or date-time
     - ie, 2008-05-21 OR 2008-05-21T11:45:30-05:00
  2. added 'verbosity=minimal' option, return below instead of full job struct
     {
	Id              string
	Name       string
	Size          int64
	SubmitTime        time.Time
	CompletedTime  time.Time
	Task          int
	State         string
    }

work?query
  1. added pagination: 'limit' and 'offset' options
  2. added sorting: 'direction' and 'order' options, order supports below fields:
      wuid, client, info.submittime, checkout_time, info.name, cmd.name,
      rank, totalwork, state, failed, info.priority
      - unknown field or default is: info.submittime