v3.1.6

[2017/11/20: v3.1.6]
Bugfix: Nested S0 struct is removed when older version is loaded.
Drift correction is improved. Three average waveforms are computed by grouping
spikes from similar center-of-mass. Now using all spikes from the same unit
previously used spikes that were centered at the peak site only.
New parameter: fSpatialMask_clu (1 by default) applies spatial masking to
the features. Half decay length set by the maxDist_site_um.
Added support to import hdf5 dataset from the Ed Boyden lab recordings for
paired intracellular recording validation.