Ensure there aren't any JSON encoding issues about centinel

[ben-jones]

@rpanah, this issue is based on an experience you had over the summer. Do you have a test case for this/ idea of what broke the JSON encoding before so that I can test this?

[rpanah]

The issue can be re-produced by running Turkey test (now removed). I believe a Unicode character in an HTML page caused JSON encoding to fail. I addressed this by encoding the HTTP test results in base64 (later changed to bz2) before adding it to JSON.

[ben-jones]

@rpanah, I don't know what version of the Turkey test caused this, but the turkey test is part of the platform, per the code at https://github.com/iclab/centinel/blob/master/centinel/experiments/turkey.py

[rpanah]

Oh, I was looking in the wrong place (the old centinel home dir). I'll run it a couple of times to see if it occurs again.