Fix issue #454
Fix issue #454

omp_get_num_threads() returns number of threads in the current team.
Outside a parallel region this is always 1.
Use #pragma omp master to print only once inside parallel region.

See:
https://gcc.gnu.org/onlinedocs/libgomp/omp_005fget_005fnum_005fthreads.html

orbitfold/tardis,kaushik94/tardis,orbitfold/tardis,Tobychev/tardis,orbitfold/tardis,Minhmo/tardis,Tobychev/tardis,kaushik94/tardis,orbitfold/tardis,Minhmo/tardis,kaushik94/tardis,Tobychev/tardis,kaushik94/tardis,Minhmo/tardis