#5 requirements text for installation

[Leo Charre]

Maybe you should have a 'requirements' section in the readme.

Compiled like a charm in one machine.. then freaked out in another.

I was missing pbm.h

I did a
# yum provides pbm.h
# yum install netpbm-devel

This could stomp some people.
I tried using 'unpaper', but the damn thing would not detect a skew.