prettyjson
  PRETTYJSON - use Java JSONObject to produce pretty JSON output
  PRETTY = PRETTYJSON(JSON_ENCODED_OBJECT, [SPACESTOINDENTEACHLEVEL])
  Given a JSON-encoded object (that is, a JSON string), this function
  produces a 'pretty' JSON output that is human-readable (one line per item,
  for example).
  SPACESTOINDENTEACHLEVEL indicates how many spaces should be used to indent each level.
  If it is not provided, 2 is used.
  This function calls JSONObject from Java, and requires the org.json.* Java classes.
  This library and its addition to the Java path is provided in
  http://github.com/VH-Lab/vhlab-thirdparty-matlab. If you have this library you
  should be all set.
  Example:
       mystruct = struct('a',5,'b',3,'c',1);
       j = jsonencodenan(mystruct) % produces single line
       j_pretty = prettyjson(j) % produces multiple lines
       % or a single line:
       j_pretty = prettyjson(jsonencodenan(mystruct))