Added ts_json_to_buffer() (example in commit msg)

The following code:

void
main(int argc, char ** argv) {
    char   obuf[1024] = { 0 };
    char * buf        = "[1, 2, 3, 4, [5, 6, 7],           "
                        "{\"stuff\" : [1,2,3,true, false], "
                        "\"things\" : \"hi\"}]\0           ";
    size_t n_read;

    ts_json_to_buffer(
        ts_json_parse_buf(buf,
                          strlen(buf) + 1, &n_read), obuf, sizeof(obuf));

    printf("%s\n", obuf);
}

Should print the following:

[1,2,3,4,[5,6,7],{"things":"hi","stuff":[1,2,3,true,false]}]