Updated "About" and "Objectives"

Syllabus updates.
Adding in attendance

And, copying in the expectations from the SCALE-UP site in doing so.
This doesn't quite show up elsewhere, but putting it in with attendance
makes sense.
Adding in a note for BlueStacks

It won't be visible to the students, but it will remain part of the
history of the course. I want them to know what we're doing, and the
problems we're facing with the tool.
Merge branch 'master' of github.com:bereacs/ba4abw-www