out= clip(in, low, high)
Clips data (scalar, vector or matrix) so that for every element
LOW <= IN<= HIGH. LOW can be '-inf', and HIGH can be 'inf', for
one sided operations.
data = input matrix, vector or scalar
low = lower scalar value
high = (optional) upper scaler value
out = clipped output data.
Examples: out = clip(in, 0) all values < 0 set = 0
out = clip(in, 0, 255) clip to [0, 255]
out = clip(in, -inf, 10) out < or = 10
Author: Peter Burns, 1 Oct. 2008
Copyright (c) 2007 Peter D. Burns