SW-488: merged TBB Alert epic branch back to trunk from https://svn.astron.nl/LOFAR/branches/SW-488-Epic_TBB_ALERT

Follow up because Cmake did not bother to rebuilt a C++ executable that depends
on the header file where I replaced the macros.

This should avoid the awkward handling.  The map makes sure that only the
central frequencies are passed around which have been used in the observation.

Also be nice an handle exceptions thrown by DAL.

SW-488: used tbb_freeze as a test routine for the new lcurun like execute_in_parallel_over_stations methods, which use the new execute_in_parallel methods

I am afraid that the 0Hz central frequency can be attributed to an integer
divided by a double.  This should at least remove the uncertainty.

SW-488: only use cep4 nodes where no datawriters are running, and ask politely for a minimum amount of nodes (not guaranteed)