Adapt DataFormats/Math to work with the new SMatrix.
use c++14 smatrix
add SMatrix constructor w/o initialization
do not zero jacobian
avoid zero in similarity
do not rezo matrices that will be soon fully filled
avoid copy constructor
avoid copy constructor
Drop spurious Math directory.
add constexpr in few more critical places
Merge pull request #3524 from VinInn/SMatrix15

add #define SMATRIX_USE_CONSTEXPR in few more critical places