control the number of threads on 'BLAS' in GNU R

 Control the number of threads on 'BLAS' (Aka 'GotoBLAS', 'OpenBLAS',
 'ACML', 'BLIS' and 'MKL'). And possible to control the number of
 threads in 'OpenMP'. Get a number of logical cores and physical cores
 if feasible.