Fixed even spline interpolator

The code was correct until I refactored it into this function.  Honest
Convert filterR and filterThroughput to arrays so as to append

Hmm. filterR and filterThroughput became np.arrays at some point
Add r1 data, and deal with per-filter radial sampling

See also bin/convertFilterData for generating these arrays
Colour by field not filter (unless --byFilter is specified)
Make --calib outputs more helpful when multiple versions are present
Convert Kawanomoto-san's filter files to numpy arrays
Added --byVisit
Redo the name mangling for coadds

The previous version didn't allocate enough bits for filters, and
adding a new filter to the list invalidated old IDs