Added comment to l4.h

Signed-off-by: Joel Nider <joel@nider.org>
joel4: Minor cleanup

Removed some unused functions and printfs

Signed-off-by: Joel Nider <joel@nider.org>
root task: updated purpose

update the comment explaining the purpose of the root task

Signed-off-by: Joel Nider <joel@nider.org>