Add hello --> world example

The example prints a GPU buffer "hello", then receives a *char from a CPU process and prints the content (world).

I think it's a good intermediate step between 01 and the previous 02. What do you think, @achilles4?

The code is not very elegant and just does this one thing. And it only works in the one configuration (CPU rank 0, GPU rank 1), as I wanted to leave the GPU code free of the word world!.

02-MSA-hello-world-gpu/Makefile

+CUCOMP  = nvcc
+CUFLAGS = -arch=sm_80
+
+ifdef EBROOTOPENMPI
+MPI_HOME+=$(EBROOTOPENMPI)
+endif
+ifdef EBROOTPSMPI
+MPI_HOME+=$(EBROOTPSMPI)
+endif
+
+INCLUDES  = -I$(MPI_HOME)/include
+LIBRARIES = -L$(MPI_HOME)/lib -lmpi
+
+all: hello.cpu.out hello.gpu.out
+
+hello.cpu.out: hello-world.c
+	mpicc $< -o $@
+
+hello.gpu.out: hello.gpu.o
+	$(CUCOMP) $(CUFLAGS) $(LIBRARIES) $< -o $@
+
+hello.gpu.o: hello-world.cu
+	$(CUCOMP) $(CUFLAGS) $(INCLUDES) -c $< -o $@
+
+.PHONY: clean
+
+clean:
+	rm -f hello.cpu.out hello.gpu.out *.o
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