CUDA implementation of MMM1D

This pull request includes my CUDA implementation of the MMM1D algorithm. A testcase is included and the command is documented in the user's guide.
Additionally, in the Espresso System Interface, energies have been integrated and a bug in particle coordinates when particle charges were enabled was fixed.
The user's guide documentation of the CPU implementation of MMM1D was also adapted to some recent changes.
Lastly, the speed of the Python blockfile parser has been improved.