removing 'using namespace', 'using somenamespace::function' and 'using somenamespace::class' from headerfiles

first version of parallelttracker with multiple dt/zstop/maxsteps in a single track command

- first step towards multiple dt in single track

When stashing and popping the bunch (needed for autophasing) then we have to do this with all cores even if some don't own any particles. The reason is that update is called which needs communication.

In autophase we stash the bunch and create a single particle on node 0. Thereafter we call itsBunch->update(). When OPAL is run in parallel then it can happen that this single particle is moved from node 0 to some other node. This we have check and act accordingly.