proposal gsl_histogram_set_ranges_uniform

[Brian Gough]

Achim Gaedke writes:
 > Sometimes it is overkill to delete an old histogram and allocate a new.
 > But for convenience this function may be added to gsl_histogram.
 > 
 > int gsl_histogram_set_ranges_uniform(gsl_histogram* h, double xmin,
 >  double xmax )

You're right, we need to have some 'init' type functions for
histograms to change ranges without reallocating.  I'll add your
function and a corresponding one for non-uniform ranges (also 2d).

 > PS: gsl_ran_gaussian_tail works...

Thanks. I've checked it into CVS now.