Add the ability to persist session cookies (issue #881).

git-svn-id: http://chromiumembedded.googlecode.com/svn/trunk/cef3@1098 5089003a-bbd8-11dd-ad1f-f1f9622dbc98
Add a new CefBrowserHost::StartDownload method for starting a download that can then be handled via CefDownloadHandler (issue #883).

git-svn-id: http://chromiumembedded.googlecode.com/svn/trunk/cef3@1100 5089003a-bbd8-11dd-ad1f-f1f9622dbc98