move slip boundary conditions to BoundaryConditions folder and deleted the following boundary conditions:

QSlipDev27;
BBSlipDevComp27;
QSlipPressureDevCompTurbulentViscosity27;
QSlipGeomDevComp27;
QSlipNormDevComp27

move velocity boundary conditions to BoundayConditions folder and deleted the following velocity boundary conditions:

BcVel27;
QVelDeviceCouette27;
QVelDevice1h27;
QVelDevCompPlusSlip27;
QVelDevCompThinWalls27;
QVelDevIncompHighNu27;
QVelDevCompHighNu27;
QVeloDevEQ27

- renamed the mpi module to parallel
- removed the communicationRoutine interface from gpu. gpu now also uses the communicator interface from parallel
- added missing functionality in parallel/Communicator
- moved ws2_32 library dependency on windows from VirtualFluids_GPU to parallel