Renamed setup_omero.sh to include an ice version
A few fixies, and move set -eux into the parent call

In theory this should make it easier to include theses script verbatim in the docs if required
Added install script for CentOS6

Note this currently uses as many distro RPMs as possible, as a consequence the installed Python modules are not the most recent available. I'll work on an updated version later.
Ensure ~omero home dir is world executable (for CentOS6)