Adjust the find Boost call, use parent scope for var

Change-Id: I526c38145ef93c4f5899bf79e9a5f120b79fcad4
Make the Boost dependency use system or superbuild

Change-Id: I15423ad7e42dee08e917c845de915539fc16712d
Updated Eigen to 3.2.1

Still won't work with Ninja generators due to Fortran probe.

Change-Id: Ic719bee55fde88e1792c059e85ecc5837744419d