Compile and test example

Compile the example:

nvcc -o hello_houston.exe hello_houston.cu

Run the example:

./hello_houston.exe
This is Houston. Say again, please.                 From Base
Houston, we have a problem in section [0,0]         From Apollo 13
Houston, we have a problem in section [1,0]         From Apollo 13
Houston, we have a problem in section [0,1]         From Apollo 13
Houston, we have a problem in section [1,1]         From Apollo 13