Base64 encode MongoBinData objects before logging.

Both the logger and the data collector for the profiler would output raw
binary data. The logger would fail due to UTF-8 warnings when doing
json_encode and the profiler queries would fail in Twig when displaying
them in mongodb.html.twig.
Swapped type and bin data when logging MongoBinData in the profiler.
Fix tests using MongoBinData to pass BYTE_ARRAY constant.
Merge pull request #177 from sellingsource/master

Base64 encode binary data before logging