Renamed CentralFrequencyOrWavelength data-type to CentralFrequency
Renamed Spectrum data-type to SpectrumBand
Removed support for legacy definitions (m,n) of channel-number and
frequency-slot to compute CentralFrequency & SpectrumBand
Refactored the frequency constraints properties of CentralFrequency
(grid-type and adjustment-granularity) into a separate (new) data-type
FrequencyConstraint.
Added FrequencyConstraint property to CentralFrequency and
SpectrumBand data-types
Renamed SpectrumType enumeration to PhotonicLayerQualifier