Add support for two factor authentication

```
What steps will reproduce the problem?
1. Put user email in user_config.py. Use one with enabled 2FA.
2. Run gcj_init_contest.py.
3. Enter correct password.

What is the expected output?
Prompt to enter 6-digit 2FA time/sms code.

What do you see instead?
Traceback (most recent call last):
File "gcj\gcj_renew_login.py", line 79, in
main()
File "gcj\gcj_renew_login.py", line 61, in main
code_jam_login.Login(options.password)
File "gcj\lib\code_jam_login.py", line 306, in Login
_, cookie = MakeLogin(host, user, password)
File "gcj\lib\code_jam_login.py", line 160, in MakeLogin
host, 'HOSTED_OR_GOOGLE', user, password, 'ah', application_name, False)
File "gcj\lib\google_login.py", line 199, in Login
source)
File "gcj\lib\google_login.py", line 125, in _GetGoogleAuthtoken
e.headers, response_dict)
File "gcj\lib\google_login.py", line 38, in __init__
self.reason = args["Error"]
AttributeError: can't set attribute

What version of the product are you using? On what operating system?
1.2-beta1, win7 x64

Workaround.
Currently we have to use application-specific password for codejam-commandline,
https://accounts.google.com/b/0/IssuedAuthSubTokens?hide_authsub=1.
```

Original issue reported on code.google.com by `jan.kill...@gmail.com` on 16 Apr 2014 at 4:57