Fix to disallow TriviaMods from accepting their own changes.

- Affects 'acceptnew', 'acceptdelete', and 'acceptedit' commands
Modified Storage.getQuestion().

- Moved the method to a more logical location
- Renamed it to Storage.getQuestionById()
More improvements.

- Updated Storage.getQuestionByRound() to return a sqlite3.Row object
- Updated methods that use Storage.getQuestionByRound() to reference
  results using keys instead of indices (for better readability)
- Fixed 'delete' command to record the user by username instead of nick
- Added error message when regex reports has fewer than 2 arguments
- Refactored 'delete' and 'report' commands to remove excess return
  statements
Cleaned up some SQL statements (issue #93) and refactoring.

- Cleaned up methods in Storage which return boolean or integer
- Small change in 'edit' command
More updates to Storage methods.

- Changed query methods that return a list of rows to use
  Cursor.fetchall()
- Updated more row references from indices to keys
Cleaned up SQL statements for retrieving top stats. (issue #93)

- Also added new messages if queries return empty lists
Fixed minor syntax errors from previous commits.