Log Message:
Update to 3.1.4:

Changes since 3.1.3:

    Bug 620: Fix robustness and performance issues in JacobiSVD::solve.
    Bug 613: Fix accuracy of SSE sqrt for very small numbers.
    Bug 608: Fix sign computation in LDLT.
    Fix write access to CwiseUnaryView expressions.
    Fix compilation of transposeInPlace() for Array expressions.
    Fix non const data() member in Array and Matrix wrappers.
    Fix a few warnings and compilation issues with recent compiler versions.
    Documentation fixes.