Bugfix: Expands ARGS collection instead of JSON

The JSON collection was being incorrectly expanded
while the user was looking up to a value on the ARGS
collection.
Bugfix: Uses JSON instead of ARGS while printing a JSON related log.

The JSON collection was being correctly expanded but it was shown
as ARGS on the logs.
Bugfix: Works correctly when the YAJL suport is disabled

The YAJL support can be disabled and enabled, if disabled
part of the code is not compiled otherwise it is.