Reuse rotation functionality in (Eigen)QuaternionManifold

Allow to specify the memory layout of quaternion coefficients using a
template parameter which defaults to Ceres coefficients order.

The changes are, for the most part, backwards compatible unless the
floating-point type is explicitly specified, e.g., as
&ceres::QuaternionToAngleAxis<double> to obtain a pointer to the
corresponding function. In such rare use cases, the coefficients order
must be given explicitly first as
ceres::QuaternionToAngleAxis<ceres::CeresQuaternionOrder>. In normal
situations, however, this should not be needed.

Change-Id: I05dd80f0593672dec656cc785cf06fe5268aee74