Report incorrect JSON
Update deps
Server that persists results

The protocol is somewhat different:

 - Another application places the request parameters in a database table
   patavi_tasks (id, method, problem, result)
 - Requests go to $patavi/ws/$id
 - Patavi checks wheter $id exists in the database table. If it does, it
   either returns the contents of the result column or runs the task
   using a worker and persists the result in said column
change table name of cache table