The periodic bcs still need to be fixed!

Squashed commits:

[cf01eebc] Change GridPath in config

This reverts commit aaba2f3a.

# Conflicts:
#	gpu.cmake
#	src/gpu/VirtualFluids_GPU/GPU/CalcMac27.cu

Develop

See merge request irmb/VirtualFluids_dev!57

This reverts commit 2ead72f4.

# Conflicts:
#	src/gpu/VirtualFluids_GPU/GPU/CalcMac27.cu

Also rename variables for length and velocity in app to make more clear whether SI units
 or LB units are used.

before only one channel side could have a velocity boundary condition (bc). When setting a bc at a second side, the first bc was overwritten.
Velocity bcs were fied in the previous commit (bda2c544271657adfabb63e9ae974e77692566a6). This commit fixes the boundaryQs for velocity.

before only one channel side could have a velocity boundary condition (bc). When setting a bc at a second side, the first bc was overwritten.

Fix memory issue.

See merge request irmb/VirtualFluids_dev!55

use new version of LBCalcMacCompSP27 again (reverts changes in bd2123ce)

(cherry picked from commit 728c8ed00d4cd9d77d1d15a581c90c5930c37ee4)

Remove loop for forcing in allocAndCopyForcing() in GridProvider and  move initParamter() in Simulation.cpp

# Conflicts:
#	apps/gpu/LBM/DrivenCavity/DrivenCavity.cpp

error introduced in ff49c380

move some lines around