network script is added move testscript in debian/rules
make check re-enabled, but data plane is disabled at this point user(nextepc/nextec) created pgwtun interface is created when PGW-preinstall script
Adding this 'debian' subdirectory will allow users to build binary packages using 'dpkg-buildpackage' and related tools. Tested so far on Debian unstable and 9 as well as Ubuntu 17.04 and 17.10 on OpenSuSE Build Service.