Review code style - brought up by @juancate

Originally, node-inotify was written following Node.JS core C++ conventions. But, there are a couple of things we could improve in terms of readability:
- Explicit name spacing is better: http://stackoverflow.com/questions/4872373/why-is-including-using-namespace-into-a-header-file-a-bad-idea-in-c
- Using C++11 may be safer and cleaner.