Issue #51 Indicate desired orientation of manipulandum.

Added text and arrows to indicate which is the upright orientation of
the manipulandum.
Issue #54 Show tapping surfaces in Collision prep.

In the task reminders the instruction to move to the blinking target is
shown with the tapping surfaces unfolded to avoid any confusion.
Issue #56 Show where VISIBLE indicator is.
Issue #59 Putting and taking mass instructions.

Created a picture that shows how to put a mass into a cradle and leave
it there and how to remove a mass from a cradle.
Issue #40 Leg position reminder.