OpenMP: copy openmp_state

[epsilonbelowzero]

I'm using the openmp_state, and got a vast template-error from gcc-7.1 when doing so. The problem lies in external/openmp/openmp_state.hpp:96. gcc complains about not beeing able to assign a std::vector< double > and double (in my case). I had to switch the line in the appropriate odeint header file from

std::copy( from[i].begin(), from[i].end(), to.begin()

to

std::copy( from[i].begin(), from[i].end(), to[i].begin()

to get it worked.

Is this the right semantically correct solution or do I miss something?