+ Display episode's timings and learning objectives.
+
+ Regarding the `if page.*** == nil` below:
+ all-in-one page combines all episodes into one.
+ It, therefore, does not define its own objectives, exercises,
+ and questions, which 'normal' episodes define in the front matter.
+
+ To display episodes' teaching and exercise times, as well as episode
+ questions and objectives, we pass them as parameters to the Liquid's
+ `include` statement when we generate the page:
+
+ include episode_overview.html teaching_time=e.teaching ...
+
+ Here we obtain the information we need either from the episode itself or
+ from the parameters passed in.