Added copy-constructible class for vectors of fixed length to substitute Eigen::Vector3d.
Updated makefile.
Merge remote-tracking branch 'espresso-clean/vector'
Added operator[] to vector class.
Added SystemInterface definition.
Added hasFeature() and null iterators to abstract interface definition.
Added generic cuda memcopy functions.
Finished GPU part of interface.
Added velocities to GPU interface.
Added missing file.
Merge branch 'master' of github.com:espressomd/espresso
Added direct request for gpu particle struct to EspSysInt
Removed self-inflicted MPI deadlock.
Removed stray debug messages.