Task #8887 #8993: Build lofar Docker images with C++11 and optimisations, use OpenBLAS instead of BLAS+LAPACK, do not build tests, pull casacore from master and casarest from jjdmol/casarest repo until C++11 fixes have been merged to main repo, drop superfluous -DLOG4CPLUS_ROOT

Task #8437: Do not set user id during build, to avoid having to add one. Also, do not run apt-get upgrade as that is unnecessary.

Task #8437: Install /opt/lofar/var als a symlink to /home/lofar/lofar/var and allow only $HOME to change ownership at start. This reduces both image boot time and any changes committed from a container

Task #8437: Change docker tags to full name of branch, for easier marshalling of branch ID between subsystems

Task #8437: Create /opt/lofar/var/{log,run} in the Docker image, and transfer ownership of /opt to calling user to allow him to write to /opt/lofar/var.

Task #9052: Generate ~/.subversion/servers in-line to prevent Docker from invalidating the cache half way in the Dockerfile