Undefined account_name in sentry files filenames

[Nitor]

Hello!

I have already described this problem in issues on Github, but I will duplicate it here. When using refreshToken for log on, sentry files are saved with sentry.undefined.bin filename because accountName is not passed to logOn method. Machine ID suffers too, because _getMachineID thinks it is anonymous logon. Machine ID is not necessary for successful authorization, but it is better to specify it. In Github issue there are links to specific code lines in library source, that cause problems. Can you fix this bug? I can make a pull request, but I'm not sure if I figured out Steam protocol and library code right.