Also map 127.0.0.1 in webviews and forward it for openExternal

Fixes https://github.com/microsoft/vscode-remote-release/issues/108

src/vs/workbench/contrib/webview/common/portMapping.ts

@@ -13,7 +13,7 @@ export function extractLocalHostUriMetaDataForPortMapping(uri: URI): { address:
 	if (uri.scheme !== 'http' && uri.scheme !== 'https') {
 		return undefined;
 	}
-	const localhostMatch = /^(localhost):(\d+)$/.exec(uri.authority);
+	const localhostMatch = /^(localhost|127\.0\.0\.1):(\d+)$/.exec(uri.authority);
 	if (!localhostMatch) {
 		return undefined;
 	}