#187 Spectrometer frequencies from Bruker files

[Geerten W. Vuister]

Upon import from a Bruker files, spectrometer frequencies of the dimensions are set from the SF parameters; this is incorrect as the SFO1, SFO2 (or SFO1 in the aqu2s), SFO3 (SFO1 aqu3s) ... are the proper values. SF denotes the base frequencies, whereas SFO1 has the actual frequency uptol the last hertz accurate (needed for proper calibration!)

[wb104]

Now uses SFO1 in acqu*s files when available.