add request parameter 'i' and 'd'
if i=y, indent the output to make it human readable
if i is missing or anything else, send the output unformatted to save bandwith
'd' defines recursion depth with a default of 1 to show the requested node
and the immediate childs (if it has any)
call /json/?i=y&d=999 for a complete property tree backup (use with caution!)
Also set the encoding to UTF-8 as required per RFC 4627
