[cs631apue] extra credit: implement revline

[Jan Schaumann]

Hello,

As I'm grading your finals, it seems that some of you might benefit from
some extra credit, and since the objective of the class is for you to
learn to program and such learning can only come from actual
programming, here it is:

Implement the revline(1) command from the in class final.
http://www.cs.stevens.edu/~jschauma/631/f11-extra.html

-Jan