split metadata call
    
    The JSON metadata call has grown large enough that parsing it requires too much stack space on some browsers.  TO avoid breaking the API, this change reuses some testing parameters that we established for the metadata call in the past.  To fetch just the objects call it like this:
    {"method":"json_metadata","params":[["all",""],{}],"id":0}
    And just the methods call it like this:
    {"method":"json_metadata","params":[["","all"],{}],"id":0}
    
    Note the difference in the positional parameters.
    
    To get a specific object,  pass the object name as the first parameter.  To get a specific method, pass a blank first parameter and the method name in the second parameter.
    
    THis is not ideal, but we are constrained by the existing API.