Purpose: Takes a bunch of intervals from different data sources and collates all intervals of the same source into a single vector(may be multidimensional) keywords: r: an array of data with dimensions [time,samples,sources] s: an array of source s[i] indices should have the source index of [*,*,i] returns: an array with dimensions [time,samples,sources] but all sources will be unique(ie the size of the output sources will be <= the input sources) Notes: --Used by thm_cal_fft,thm_cal_fbk --The returned data will be sorted according to source index in ascending order