Create Java NIO fs watcher implementation

[oubiwann]

cmr.dev.env.manager.watcher.impl.nio

See:

• https://docs.oracle.com/javase/7/docs/api/java/nio/file/FileSystem.html#newWatchService()
• https://docs.oracle.com/javase/7/docs/api/java/nio/file/WatchService.html
• https://docs.oracle.com/javase/7/docs/api/java/nio/file/Path.html#register(java.nio.file.WatchService,%20java.nio.file.WatchEvent.Kind...)
• https://docs.oracle.com/javase/7/docs/api/java/nio/file/StandardWatchEventKinds.html
• http://markusjais.com/file-system-events-with-java-7/