Apparently we've reached the limit of GitHub rendering (512K).
Time to change the structure accordingly - exercises and questions
will move to sub-directories in the exercises directory.
This is the first patch in performing this transition.
Instead of having exercises in their own separate section,
they are now part of the main topics sections.
This should make the learning process easier to follow
where users have both exercises and questions in the same
place.
In addition, added a couple of new questions & exercises
and modified existing scripts accordingly.
