It doesn't look very good for "native" apps to overscroll when scrolling. Would be nice to have a BrowserWindow option to disable overscroll

![untitled12](https://cloud.githubusercontent.com/assets/170270/15033357/fc36e32e-1293-11e6-8cdc-6c17b0f504dd.gif)
## 
- Electron version: 0.37.8
- Operating system: OS X 10.11.4

atom/renderer/atom_renderer_client.cc
#include "atom/renderer/atom_renderer_client.h"
#include <string>
#include <vector>
#include "atom/common/api/api_messages.h"
#include "atom/common/api/atom_bindings.h"
#include "atom/common/api/event_emitter_caller.h"
#include "atom/common/color_util.h"