Started cleaning up LB.
Updated list of AUTHORS
Small changes to DG
Use enum instead of int for Coulomb method.
Added default cases.
Merge remote-tracking branch 'espresso/master' into mmm1dgpu

Unresolved issue with beee052f58e69d1b5e1a14a3710315339478b2e5:
cuda_common_cuda.cu now includes energy.hpp, but that commit forbids including files depending on mpi.h in *.cu files.

Conflicts:
	src/core/interaction_data.hpp