INPUT: oldBins is a list of bin edges. It contains n>=2 unique elements sorted in ascending order newBins is a list of bin edges. It contains m>=2 unique elements sorted in ascending order oldVals is a list of n-1 values associated to oldBins, the values to interpolate. That is, oldVals[i] is associated with the bin having edges (oldBins[i], oldBins[i+1]). flux set means oldVals are counts/binWidth, not counts OUTPUT: returns a list of m-1 interpolated values associated to newBins METHOD: traverse both bin lists once. For each old bin there are 4 possibilities: a) old bin precedes current new bin b) new bin precedes the current old bin c) old bin overlaps new bin, extends beyond d) old bin overlaps new bin, does not extend beyond CALLS: none NOTES: 1. algorithm is simple linear interpolation. 2. The interpolated vector might contain less information than the input vector. Exchanging oldBins and newBins is not an inverse function for brl_rebin(). 3. Difference between FLUX=0 and FLUX=1: suppose the old and new binning schemes have the same total range. Then FLUX=0 preserves the sum of oldVals, and would be used when oldVals represents counts in each bin, whereas FLUX=1 preserves the dot product of oldVals and the (n-1 length) vector of differences between successive oldBin entries---used when oldVals has counts divided by bin width. WARNING: since this might be called repeatedly with only oldVals changing, error-checking is minimal. The calling routine is responsible for error-checking. REVISION HISTORY: works, not much testing mm/Jul 2012 22Oct2012: corrected normalization for flux eq 0 01Jan2013: calculates array lengths n&m automatically (DMS)