Implement linalg.lstsq

[Oceania2018]

Return the least-squares solution to a linear matrix equation.
https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.linalg.lstsq.html

[dotChris90]

@Oceania2018 After QR now will try dgels_ but .... get the "memory corruption" error -.- when finding out the correct cast values, can do this lstsq

[dotChris90]

@Oceania2018 I will keep this issue open - the implementation at moment just return the param array - but according to numpy doc - there are much more output like residuals, rank, singular values, ...

Side note
From my point of view they also just use LAPACK since the output of them is 100% the same like LAPACK outputs. lol

[Oceania2018]

really, I thought umath is another library.

[dotChris90]

not sure. I just know the portable windows python version have just one lapack lite. but yes u are right the normal python has a 2nd dll there

[dotChris90]

This need to implement the other return types like error etc