Update README.WPF.md

Rename WebView to ChromiumWebBrowser and make a few minor adjustments to show a minimal CefSharp3 implementation.
Fixed #464 NullReferenceException when browser is disposed while focused
Merge pull request #485 from amaitland/fix/dispose-nullpointer

Fixed #464 NullReferenceException when browser is disposed while focused
provide access to settings boolean ignore_certificate_errors
Merge pull request #488 from karlhiramoto/certs

provide access to settings boolean ignore_certificate_errors
Merge remote-tracking branch 'remotes/upstream/master' into JsBinding/Wip2