Add SVD to GaussNewtonOptimizer

Allow using the SVD decomposition which has excellent stability and can
provide a "solution" for singular problems.

Figured out why one of the least squares tests did not check two of the
states. There was only one equation for the two states. The test now
verifies the states satisfy the constraint.

Patch provided by Evan Ward.

JIRA: MATH-1104

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1573351 13f79535-47bb-0310-9956-ffa450edef68