1.3.4: Add support for more types of challenges
1.3.4: Add support for more types of challenges

Added support for:
- Dialog (get a question in the target language and select the right answer)
- Reading comprehension (read a short paragraph and answer a multiple
  selection question).
- TapCloze (grammar exercise, select the right ending for a word).
- TypeCloze (grammar exercise, typ the right ending for a word).
- GapFill (choose the missing word in a sentence).

TODO: Remove dead code. There are challenges that were possibly removed
from Duo, and are now just dead code. E.g: I haven't seen a
JudgeChallenge in a while, and suspect they are gone.

camiloaa/duolingotreeenhancer