Revision 721203

completed implementation of EigenDecompositionImpl.
The implementation is now based on the very fast and accurate dqd/dqds algorithm.
It is faster than Jama for all dimensions and speed gain increases with dimensions.
The gain is about 30% below dimension 100, about 50% around dimension 250 and about
65% for dimensions around 700.
It is also possible to compute only eigenvalues (and hence saving computation of
eigenvectors, thus even increasing the speed gain).
JIRA: MATH-220