RegisterJsObject should be in IWebBrowser, so we can more easily utilize it from unit tests.
Got rid of the (defunct and partially commented out) Popup code. We didn't have full OSR popup handling anyway; what might be worthwhile is perhaps trying to detect popup windows being opened so you can open them in a separate tab or similar. There has been some discussion about our current popup handling so perhaps someone wants to step up and work on it eventually.
WinForms references, which should definitely not be here.
Ugly workaround for the recently discovered bug w/ #140. We must detect the case when we are the rendering process, so we shutdown once CEF is done. :) Obviously, we should fix #138 and I started looking into it but it seemed non-trivial so it will have to wait a little bit further until we do it.