Writing tutorials on reduction and scan.

Documentation/Tutorials/CMakeLists.txt

Documentation/Tutorials/ReductionAndScan/CMakeLists.txt

...entation/Tutorials/ReductionAndScan/MapReduceExample-1.cu

...entation/Tutorials/ReductionAndScan/MapReduceExample-2.cu

...entation/Tutorials/ReductionAndScan/MapReduceExample-3.cu

...tion/Tutorials/ReductionAndScan/ReductionWithArgument.cpp

...ation/Tutorials/ReductionAndScan/ReductionWithArgument.cu

Documentation/Tutorials/ReductionAndScan/ScanExample.cpp

Documentation/Tutorials/ReductionAndScan/ScanExample.cu

...ation/Tutorials/ReductionAndScan/tutorial_03_Reduction.md