fliege sampling does not seem to be correct

[ahms5]

looks like the fliege sampling, which is precalculated from another toolbox isnt corret.
its neither a quadrature nor the sampling weights sum to 4pi.

@mberz suggested to use this source instead: https://www.personal.soton.ac.uk/jf1w07/nodes/nodes.html
the filenames are named after the number of points (n_max+1)**2 and include weights.

this issue came up in #269

It is also ment to be a quadrature after https://www.personal.soton.ac.uk/jf1w07/nodes/nodes.html, so this should also be tested.