Fix bug #503

C++11 support on simple allocators comes for free. `aligned_allocator` does not
need to add any `construct` overloads to work with C++11 compilers.
Silence unused variable warning.
Add cmake config files
Merged in vanhoucke/eigen_vanhoucke_unused_variable (pull request #34)

Silence unused variable warning.
Fix bug 672: use exceptions in SuperLU if they are enabled only
Merged in xantares/eigen (pull request #36)

Add cmake config files
Merged in martinhofernandes/eigen (pull request #33)

Fix for bug #503
Use aligned loads in Matrix-Vector product where possible. Fixes Bug 689
Fix parenthesis min/max issue in mpreal
Fix unused variable warnings
Fix bug 678: vectors of row and columns transpositions were not properly resized in FullPivQR