Function jsonObject( txt )

Description:
Converts the supplied string to a JSONObject which can be interrogated further. If the input string doesn't have the syntax of a JSON object, an empty JSONObject will be returned.

The JSON parsing is currently somewhat lenient, for instance allowing a comma before a closing curly bracket.

Parameters:
txt (String)
string assumed to contain a JSON object
Return Value (JSONObject):
JSON object value on which further methods can be called
Signature:
JSONObject jsonObject(String)