• fixes #691
• Deprecating SS_LOG_VERBOSE_LEVEL and SS_LOG_WITHOUT_TIME environment variable.

I'd like to have ssserver be in verbose logging mode on my shadowsocks-rust deployment via snap. However, snap doesn't make it easy to pass command-line arguments to its services. I use a config file instead.

The problem is, there doesn't seem to be a way, documented or otherwise, to set the logging level to verbose in the config file, despite being able to set just about everything else. This strikes me as unintentional.

• fixes #691

• fixes #698
• Refactored shadowsocks-rust crate structure. Common code are put into a separated library

For proxy tools, source code that are required by client is also required by server, in theory. sslocal, ssserver, ssmanager shares a lot of common source code. Static-link build them apart is wasting storage space.As of ssurl, it's something 'one line code'. I suggest build them into one single binary file, with switch flag, like --local, --server, --manager, --encode, --decode.

Recent commit made some new change, I have some suggestion about them:

1. Add 'working directory', 'executable location' to Default config path.
2. Put log level setting in config.json like nginx, httpd. Furthermore, make this as SIP standard? PS: I don't know if there is any SIP standard for config.json. As far as I know , ss-rust using some different keyword from libev, for port as server_port.
3. Print loaded config path, log level setting to stdout during startup, for better user-understanding ,before they post any new issue about config.