TODO list for Perl module Statistics::LineFit

Test and document what happens as the sum of the deviations of the x
values approaches zero.

Test and document the sensitivity of the results to random and Gaussian
noise.

Abstract this module into a class hierarchy that can do N-dimensional line
fitting, curve fitting, cubic splines fitting, non-linear regression, etc.
(This would require major coordination / major rewrites with / of the other 
Statistics:: modules.)