Don't use "master_seed"! master_seed "False" in config, users.json without master_seed will result in "siteSign" failure, missing auth_addresses in users.json, updates not working!! :/

```
Traceback (most recent call last):
File "zeronet.py", line 17, in main
main.start()
File "/opt/zero/src/main.py", line 589, in start
actions.call(config.action, action_kwargs)
File "/opt/zero/src/main.py", line 123, in call
back = func(**kwargs)
File "/opt/zero/src/main.py", line 206, in siteSign
site_data = user.getSiteData(address)
File "/opt/zero/src/User/User.py", line 78, in getSiteData
self.generateAuthAddress(address)
File "/opt/zero/src/util/Noparallel.py", line 57, in wrapper
raise(err)
File "/opt/zero/src/util/Noparallel.py", line 50, in wrapper
res = func(*args, **kwargs)
File "/opt/zero/src/User/User.py", line 63, in generateAuthAddress
auth_privatekey = CryptBitcoin.hdPrivatekey(self.master_seed, address_id)
File "/opt/zero/src/Crypt/CryptBitcoin.py", line 69, in hdPrivatekey
masterkey = btctools.bip32_master_key(bytes(seed, "ascii"))
TypeError: encoding without a string argument
```

I urge everyone who using ZeroNet **not to use "master_seed"** at all! @HelloZeroNet and @imachug working on Windows and Google Chrome and they have been notified prior to turn "master_seed" off!

Start with the siteSign traceback in src/main.py, then inspect src/User/User.py and src/Crypt/CryptBitcoin.py around getSiteData, generateAuthAddress, and hdPrivatekey. Reproduce the failure with a users.json lacking master_seed and verify that siteSign no longer raises the reported TypeError and that auth_addresses are handled correctly.

索引モデルが issue の本文から書いたものです。