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.
use c++14 smatrix
add SMatrix constructor w/o initialization
do not zero jacobian
avoid zero in similarity
Drop spurious Math directory.
add constexpr in few more critical places
Merge pull request #3663 from ktf/smatrix-integration

Performance -- Adapt CMSSW to work with the new SMatrix.