Changes:
* Terminate all namespaces with the correct closing comment.
* Make sure argument names in comments match the corresponding parameter name.
* Remove redundant get() calls on smart pointers.
* Prefer using "override" or "final" instead of "virtual". Remove "virtual" where appropriate.
`unittests/Basic/BlotMapVectorTest.cpp` references `llvm::outs()`, which is defined in `llvm/Support/raw_ostream.h`. I believe this currently works without the import because it is transitively included via some CMake incantations and conditionals in the googletest headers invovling `GTEST_NO_LLVM_RAW_OSTREAM`. I'm not sure.
In any case, including the header is more explicit. The file uses `llvm::outs()`, so it should include the header that defines it.
