Fixed routing

- Realized I didn't want to get status by id from the main timeline; that should
  always be based on user
- Fixed criteria for both user and id (to remove anchors; not needed, and caused
  inability to match)
Functional testing fixes

- Added missing exception classes
- Status class needed to allow setting null values on most setters;
  additionally, since data came in from DB as strings, timestamp setter
  needed to allow strings.
- StatusDbPersistence needed to cast incoming data to an array (often
  receiving stdClass objects due to json-deserialization); also needed
  to cast on onFetch to array before returning
- StatusValidator had some runtime errors related to use of trim()
  inside empty()