CEF 2171

Migrate Mac and Windows to CEF 2171. 
NOTE: The Linux builds will either fail or fail to start/terminate on this branch.  
Linux will continue to use CEF 1547 until the issue has been addressed
Great! This seems to be one missing piece for the Linux issue. I had to call `CefQuitMessageLoop` here, but it felt kinda a hacky. Now that I see the code, I feel some sort of relief.