Task #4589: Reintegrated task branch (Fix BeamFormerSubbandProc for Incoherent Stokes) with the trunk.

Task #5049: reference for rotationangle should be possible (same as rev. 27358, but accidentally committed to branch instead of trunk)

Task #4589: Rewrote test for the Beam-former sub-band processor. Still needs some improvement, but it may be fine for now.

Task #4589: Added possibility to enable/disable bandpass correction in the new BandPassCorrection kernel. This is really useful for testing. Note that this commit does not really belong to issue #4589, but this was by far the easiest way to add it.

Task #2669: upd variants for sharkbay. CUDADRIVER_ROOT_DIR disabled, as the NVIDIA driver is not installed yet (GPU not detected).

Task #4589: First working version of the *incoherent* part of the beam-former pipeline. Verified correctness of all intermediate kernel outputs with a sine wave of half the Nyquist frequency as input.

Task #5028:Changes in order to compile and run the the pipelines on the Juropa Cluster in Juelich. Necessary due to different operating system and hardware architecture. Reviewed by Wouter.

Task #5028: merge from release branch to changes needed to run in juropa. Excluding parset adaptions

Task #2669: update my variants file with symlink for ccache. Parallel build performance is a lot faster for me after the first time.

Task #2669: fix powerOfTwo() bug for n=0. Also for n=INT_MIN. Negative numbers are not a power of 2. Avoid undefined behavior on signed arithmetic. Remove separate assertion elsewhere for case n=0, as it is now covered.

Task #3185: make sigint_seen volatile in new TBB Writer. Touching stuff in signal handlers that is not volatile or sig_atomic_t is apparently undefined behavior.

Task #4624: Added key _DPname to default.parset; needed for tProductionParset. Disabled the MACCLP socket appender, because it triggers random segmentation faults in rtcp.

Task #4956: Ignore 'real' pset number, because it does not match for LOFARTEST, which contains psets that we don't use