Remove Uint4 from Code Eventually

[GNiendorf]

The current solution in the code works fine for the NVCC and CPU backends, but if we want to make use of the other backends we will have to remove uint4 to make the code completely general to whatever backend we are running.

TrackLooper/SDL/Constants.h

Lines 46 to 56 in 9c0c03c

	// Needed for files that are compiled by g++ to not throw an error.
	// uint4 is defined only for CUDA, so we will have to revisit this soon when running on other backends.
	#ifndef ALPAKA_ACC_GPU_CUDA_ENABLED
	struct uint4
	{
	unsigned int x;
	unsigned int y;
	unsigned int z;
	unsigned int w;
	};
	#endif