fix cuSTL::algorithm::mpi::Gather and Reduce

- add method cuSTL::zone:SphericZone::within()
make ThermalTest ready for big runs

- not longer restricted to e.g. -d 1 1 64, instead -d 4 4 4 is allowed too
- 16 particles/cell
- 40 MB communication buffer per face
fix bug in cuSTL::algorithm::mpi::Reduce

- len -> len/sizeof(type)
add license header and change to 16 particles/cell
readd Axel Huebl to the copyright list.
Merge pull request #26 from Heikman/ThermalTest

Thermal test update for big runs