help the term "OP" become obsolete

#define EXIT_PURPOSE_RESOLVE 2

#define _EXIT_PURPOSE_MAX 2

/** Circuit state: I'm the OP, still haven't done all my handshakes. */

/** Circuit state: I'm the origin, still haven't done all my handshakes. */

#define CIRCUIT_STATE_BUILDING 0

/** Circuit state: Waiting to process the onionskin. */

#define CIRCUIT_STATE_ONIONSKIN_PENDING 1

#define CIRCUIT_PURPOSE_TESTING 17

#define _CIRCUIT_PURPOSE_MAX 17

/** True iff the circuit purpose <b>p</b> is for a circuit at the OP

 * that this OP has originated. */

/** True iff the circuit purpose <b>p</b> is for a circuit that

 * originated at this node. */

#define CIRCUIT_PURPOSE_IS_ORIGIN(p) ((p)>_CIRCUIT_PURPOSE_OR_MAX)

#define CIRCUIT_IS_ORIGIN(c) (CIRCUIT_PURPOSE_IS_ORIGIN((c)->purpose))

#define RELAY_HEADER_SIZE (1+2+2+4+2)

#define RELAY_PAYLOAD_SIZE (CELL_PAYLOAD_SIZE-RELAY_HEADER_SIZE)

/** Parsed onion routing cell.  All communication from OP-to-OR, or from

 * OR-to-OR, is via cells. */

/** Parsed onion routing cell.  All communication between nodes

 * is via cells. */

typedef struct {

  uint16_t circ_id; /**< Circuit which received the cell. */

  uint8_t command; /**< Type of the cell: one of PADDING, CREATE, RELAY,

 * data.

 *

 * A connection is named based on what it's connected to -- an "OR

 * connection" has an onion router on the other end, an "OP connection"

 * (nearly obsolete) has an onion proxy on the other end, an "exit

 * connection" has a Tor node on the other end, an "exit

 * connection" has a website or other server on the other end, and an

 * "AP connection" has an application proxy (and thus a user) on the

 * other end.

  char *nickname; /**< Human-readable OR name. */

  uint32_t addr; /**< IPv4 address of OR, in host order. */

  uint16_t or_port; /**< Port for OR-to-OR and OP-to-OR connections. */

  uint16_t or_port; /**< Port for TLS connections. */

  uint16_t dir_port; /**< Port for HTTP directory connections. */

  crypto_pk_env_t *onion_pkey; /**< Public RSA key for onions. */