Gerrit: Differentiate by approval type.

- Parse approval type and description.
- Format tooltip as HTML table, listing approvals by type
- Format the approval column similar to the web view by
  type character.
- Fix the special character issue in Qt 4.8 (query tool
  actually outputs UTF8 instead of escapes).

Change-Id: I803f289a03c5a8ede0029d972a19381b5e783d36
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>