im thinking of streamlining the operators here.  Looking at http://www.postgresql.org/docs/9.3/static/functions-json.html it seems like our operators are: getitem, getarray, and then both have the option to be "text".

so how about this:

    json_col['some_element']    # get the element
    json_col.astext['some_element']    # get the element as text
    json_col[('a', 'b', 2)]  # get by path
    json_col.astext[('a', 'b', 2)] # get by path as text

seems like also these ops are only in pg 9.3....ill add some qualifiers to the tests and I also want to add some round trips for these.   going to install 9.3 now...