Added LOFAR_TOPOCENTRIC_FREQUENCY_CORRECTION_APPLIED field (doppler correction)
Added LOFAR_TOPOCENTRIC_FREQUENCY_CORRECTION_APPLIED field to SPECTRAL_WINDOW table to describe "doppler correction" as applied by COBALT.
See also lofar!654 (merged) and https://support.astron.nl/jira/browse/COB-256