[FIX] survey: various fixes

(see internal tickets 609979, 610789)

- [x] add `oe_no_empty` class to various `t-field`s
- [x] remove stupid duplicated browse record
- [x] clarify content of `survey_result` dictionary
- [x] unfuck `comment_count_as_answer` option
- [x] change `prepare_result_dict` to load comment answers
- [x] display comment answers in reporting
- [x] skipped answers are not counted properly