Generalized eigenvalue problems with range selection

I think I am done with the methods now:

* All range inputs are checked in the Eigen class and exceptions thrown if something is wrong. I have tested to add bad arguments in the method call and I think all stupid things you can do are covered.
* Range indices are 0-based.
* A NoEigenResultException is thrown if no eigenvalues (and eigenvectors) are found when working with value ranges.

The classes effected are:
* org.jblas.SimpleBlas
* org.jblas.Eigen
* org.jblas.exceptions.NoEigenResultException