fix read offset bug based a patch Bradford Powell submitted to the iRODS-Chat

git-svn-id: svn://irodssvn.ucsd.edu/trunk@5566 ea137bd6-aa86-47b6-b90d-b101d9f19a90
more changes based on Bradford Powell's suggestions on iRODS-Chat

git-svn-id: svn://irodssvn.ucsd.edu/trunk@5567 ea137bd6-aa86-47b6-b90d-b101d9f19a90
more fixes

git-svn-id: svn://irodssvn.ucsd.edu/trunk@5568 ea137bd6-aa86-47b6-b90d-b101d9f19a90