Improve task description storage, sanitize descriptions using Jsoup
Use Jsoup to sanitize task descriptions. Changes to storage were made 
to facilitate sanitization.
Schema changes: improve database performance
Add "score" to the solutions table. This removes the need to do a join
on the whole verdict table. Change the "message" column to "status" in
the verdicts table - there is no need for it to be a VARCHAR, so we
just store it as an enum (integer in the DB).