node: arrangement of global interfaces

This is a logical continuation of #2002. I didn't reset commits, because they include not only renaming, but removing unnecessary links with global instead modules.

* Create module `NodeJS` for **global** interfaces
* Mark `NodeBuffer` as deprecated and create `Buffer`
* Move `ErrnoException` to `NodeJS`
* Move `ReadableStream` to `NodeJS`
* Move `WritableStream` to `NodeJS`
* Rename `ReadWriteStream` to `NodeJS`
* Make external modules dependent on `stream.*`, not globals, when possible.
* Make external modules dependent on `events.EventEmitter`, not `NodeJS.EventEmitter`

How long to keep `NodeBuffer`?