(sftp_get_data): ...but do it here instead.
(sftp_free_string): Reintroduced this function.
(sftp_get_string): This function now requires the user to
deallocate the string.
(sftp_get_string_auto): Simpler function, that deallocates strings
automatically.
(sftp_read_packet): Return failure (0), rather than crashing, if
there is data leftover from the previous packet.
(sftp_put_final_length): Calculate the length correctly.
(sftp_put_reset): Fixed assertion.
(sftp_put_attrib): Likewise.

Rev: src/sftp/buffer.c:1.5
Rev: src/sftp/buffer.h:1.5