Merge pull request #4202 from evgenyzinoviev/shadow-pr

Added hasShadow option to BrowserWindow on OS X

diff --cc atom/browser/api/atom_api_window.cc
Simple merge

diff --cc atom/browser/api/atom_api_window.h
Simple merge

diff --cc atom/browser/native_window.cc
Simple merge

diff --cc atom/browser/native_window.h
Simple merge

diff --cc atom/browser/native_window_mac.h
Simple merge

diff --cc atom/browser/native_window_mac.mm
Simple merge

diff --cc atom/common/options_switches.cc
Simple merge

diff --cc atom/common/options_switches.h
Simple merge

diff --cc docs/api/browser-window.md
Simple merge