Add grouping function from MALDIquant

[jorainer]

Would be great to have the grouping function from MALDIquant here in MsCoreUtils as it could be re-used in various other packages (e.g. MsFeatures, but also xcms et al). The initial description is here - maybe @sgibb , you could add it? This could be a nice alternative to group() as it splits the data based on difference instead of grouping based on difference between individual values.