Added comments to DppViewModel etc.
Changed the type of DataProcessingRegion from Region to IntRegion.
Implemented IntRegion.Parse, IntRegion.TryParse, IntRegionTypeConverter etc....
Renamed namespace: Xbrt.Spectral.PeakFitting -> PF
Refactoring of PeakFittingViewModel.
Renamed some internal arguments.
Added MaixmumEnergy_eV to the project etc.
Cosmetic changes
Removed inheritance from NotificationObject from Line, LineGroup, Shell.
Removed Normalize and IsNormalized from LineGroup, Shell.
Removed RealativeIntensity from LineGroup.
Re-generated shells.xml
Added AtomicNumber to the LineInfoCollection and make it read-only.
Added Database.Shells
Removed Database.LoadLineGroups
Added relationship.
Removed LineInfo from public interface of Fluorescent.
Removed LineInfo from public interface of PeakFittingViewModel.
Removed LineGroup from IDatabase interface.
Removed files no longer used.
Removed LineInfo and LineInfoCollection from PeakFittingViewModel.
Line.LineGroup=>Line.Group etc.