Added json-metalist program to report metadata given a JSON stream

Added a new baton_error_t parameter to json_to_path to detect errors
in user input

Fixed a double free on error bug on the query_input argument to
do_query
Merge branch 'devel' of github.com:keithj/baton into devel
Merge pull request #26 from keithj/devel

Added json-metalist program