nseig (NonSymetricEigenvalues and revisited balance it uses. poly and ro...

...ts call nseig

I found out that I cant easibly modify symeig_update. So I will split it in small pieces.
This is the first one containing the non symetric eigenvalue computation nseig based on lapack geev
and its associated balance process based on gebal and gebak.

poly and roots now use nseig.

The other updates will follow for lu qr svd chol etc. in following requests.
ok change the header guard