[HIPIFY][CUB] Initial support (hipify-clang only)

+ Add one matcher (will be more)
+ Update Maps and Statistics
+ Add cub_01.cu unit test
+ Update lit harness to support standalone CUB
+ Update README.md
+ Update hipify-perl (only CUB header is supported for now)

[IMPORTANT]
clang (and hipify-clang) works correctly only with official NVLabs version on GitHub.
Compilation of CUB from official CUDA release has conflicts with THRUST.
Thus, to compile CUB sources, option "-I" should be specified to the cloned CUB from NVLAB on GitHub.

hipify-clang/src/Statistics.cpp

@@ -129,6 +129,7 @@ const char *apiTypes[NUM_API_TYPES] = {
   "API_RAND",
   "API_DNN",
   "API_FFT",
+  "API_CUB",
   "API_SPARSE",
   "API_CAFFE2"
 };