Path fix for windows - leading slash

Looks like there is some junk with Windows paths. To put it simply, the
following call is an Identity operation under Linux, but leaves a
leading slash under Windows:

url.parse( url.format( { pathname: path.join(process.cwd(), 'got_access_token.html'), protocol: 'elif:', slashes: true } )).pathname

On windows you get '/E:/some/path/...' - note the leading slash.

Some discussions here:
  nodejs/node#10703
  nodejs/node#10739

Dunno! I just fixed it by hand.

main.js

@@ -61,7 +61,7 @@ app.on('ready', () => {
 
   // Chromium prevents redir to file://. See https://github.com/electron/electron/issues/9077
   electron.protocol.registerFileProtocol('elif', (request, callback) => {
-    const path = url.parse(request.url).pathname;
+    const path = url.parse(request.url).pathname.replace(/^\/(\w:)/, '$1');
     callback({ path });
   }, (error) => {
     if (error) console.error('Failed to register protocol');