- Electron version: v0.37.5
- Operating system: Any

It would be useful if we can open DevTools choosing all of it's available position: detached, docked right or docked bottom.

The new API could be something like this:
# webContents.openDevTools([options])

Opens the devtools.
- options Object (optional)
  - mode String - ['detached' | 'right' | 'bottom'] . opens DevTools in specified position. Defaults to last used mode.
  - detach Boolean - opens DevTools in a new window (deprecated, use mode: 'detached')

atom/browser/api/atom_api_web_contents.cc
.SetMethod("unselect", &WebContents::Unselect)
      .SetMethod("replace", &WebContents::Replace)
      .SetMethod("replaceMisspelling", &WebContents::ReplaceMisspelling)
      .SetMethod("findInPage", &WebContents::FindInPage)
      .SetMethod("stopFindInPage", &WebContents::StopFindInPage)
      .SetMethod("focus", &WebContents::Focus)
      .SetMethod("tabTraverse", &WebContents::TabTraverse)
      .SetMethod("_send", &WebContents::SendIPCMessage)
      .SetMethod("sendInputEvent", &WebContents::SendInputEvent)
      .SetMethod("beginFrameSubscription",
                 &WebContents::BeginFrameSubscription)
      .SetMethod("endFrameSubscription", &WebContents::EndFrameSubscription)
      .SetMethod("setSize", &WebContents::SetSize)
      .SetMethod("isGuest", &WebContents::IsGuest)
      .SetMethod("getWebPreferences", &WebContents::GetWebPreferences)
      .SetMethod("getOwnerBrowserWindow", &WebContents::GetOwnerBrowserWindow)
      .SetMethod("hasServiceWorker", &WebContents::HasServiceWorker)
      .SetMethod("unregisterServiceWorker",
                 &WebContents::UnregisterServiceWorker)
      .SetMethod("inspectServiceWorker", &WebContents::InspectServiceWorker)
      .SetMethod("print", &WebContents::Print)
      .SetMethod("_printToPDF", &WebContents::PrintToPDF)
      .SetMethod("addWorkSpace", &WebContents::AddWorkSpace)
      .SetMethod("removeWorkSpace", &WebContents::RemoveWorkSpace)
      .SetProperty("session", &WebContents::Session)
      .SetProperty("hostWebContents", &WebContents::HostWebContents)
      .SetProperty("devToolsWebContents", &WebContents::DevToolsWebContents)
      .SetProperty("debugger", &WebContents::Debugger);
}
AtomBrowserContext* WebContents::GetBrowserContext() const {