Password saves incorrectly in ss-local-config.json.

[behzadsh]

Describe the bug
Seems like app escapes slashes / before saving it in ss-local-config.json.

To Reproduce
Add a password that contains / and gets an invalid password message in logs.
After checking logs for finding the reason why my shadowsocks is not working, I checked ss-local-config.json and see that / in my password was escaped. I removed escaping back-slash and check the connection and it was fine.

Expected behavior
Slashes should not be escaped before saving in ss-local-config.json.

System and Shadowsocksx-NG version: (please complete the following information):

• OS Version: 10.14.6
• Version 1.8.2

ss-local.log

Please upload the ss-local.log file here the file is in ~/Library/Logs

1. Open 'Advanced Settings -> enable Verbose Mode'
2. Continue run Shadowsocksx-NG for 5 minutes
3. Upload the ~/Library/Logs/ss-local.log here (with or without compress)

Application log

...
 2019-09-02 21:34:02 ERROR: invalid password or cipher
 2019-09-02 21:34:03 ERROR: invalid password or cipher
 2019-09-02 21:34:04 ERROR: invalid password or cipher
 2019-09-02 21:34:04 ERROR: invalid password or cipher
 2019-09-02 21:34:04 ERROR: invalid password or cipher
 2019-09-02 21:34:04 ERROR: invalid password or cipher
 2019-09-02 21:34:05 ERROR: invalid password or cipher
...

[qiuyuzhou]

This is NSJSONSerialization.dataWithJSONObject that likes to insert additional backslashes.
Escaped forward slashes is also valid json. May be ss-local hasn't handle it correctly.

Need a workaround.