GE
  [subs,vals,keep] = nonMaxSuprList( subs, vals, radii, ...
    [thresh], [maxn], [flag] )

 INPUTS
  subs       - subscripts of point locations (m x d)
  vals       - values at point locations (m x 1)
  radii      - suppression window dimensions
  thresh     - [] minimum value below which not to look for (or [])
  maxn       - [] return at most maxn of the largest vals
  flag       - [] suppress equal vals (see above)

 OUTPUTS
  subs       - subscripts of non-suppressed point locations (n 