Memory leak when social or embeded websocket server are enabled

[mesvam]

Steps to Reproduce

./run.sh config.json.example
and wait ~10 minutes

Actual Behavior

Memory usage starts at ~75 MiB, but goes up to ~150 MiB in 10 minutes. If left running, memory usage continues to grow and thrashes the computer to an unusable state.

Config

I tested using the default config.json.example with a few tasks disabled to isolate the cause:

Workaround

In the config, change
enable_social to false
and also remove this section at the end

    "websocket": {
        "start_embedded_server": true,
        "server_url": "127.0.0.1:4000"
    }

(No, simply setting start_embedded_server to false does not seem to make a difference for some reason. You need to remove that entire block.)

With this fix, memory usage stabilized around ~70 MiB.

By the way, I'm not sure what these settings actually do or why, but changing them just happens to work for me. (If somebody could explain, that would be great, because that websocket and start_embedded_server isn't documented anywhere) If it works for others too, could I suggest pushing these changes to the default *.example configs until the underlying cause is fixed?

System info

Linux Mint 17.3 Cinnamon 64-bit
Python 2.7.6
Branch: dev & master