couchdbkit show function support

show_function.py

    def show(self, show_name, doc_id, **params):
        """ Execute a show function on the server and return the response.
        If the response is json it will be deserialized, otherwise the string
        will be returned.

        Args:
            @param show_name: should be 'designname/showname'
            @param doc_id: id of the document to pass into the show document
            @param params: params of the show
        """
        show_name = show_name.split('/')
        dname = show_name.pop(0)
        vname = '/'.join(show_name)
        show_path = '_design/%s/_show/%s/%s' % (dname, vname, doc_id)

        return self.res.get(show_path, **params).json_body