Add task box or change question boxes
Question boxes only show up in the solution document if there is an answer section like:
\begin{question}
...
\end{question}
\begin{answer}
\end{answer}
It would be nice if the question would still show up in the solution document even if there is no answer. Alternatively we could create a new type of box (maybe called task) that looks like a question box but does not have answer section.