Fix memory leaks in unit tests

Release 1.17.2

- [BUGFIX] Memory leak in test_frame_rw unit test.
- [BUGFIX] Parsing packets with short IETF header: do not overwrite
  flags.  (Only a problem in unit tests -- benign otherwise.)

Packet out Memory Interface (PMI) update; bug fixes

Release 1.17.0

- [API Change] Packet out Memory Interface (PMI) update:
  - Split PMI pool return into pmi_release and pmi_return
  - PMI callbacks take peer_ctx and is_ipv6 arguments
- [BUGFIX] Fix use-after-free when certificate is updated
- Silence gcc warning in optimized mode by performing useless
  initialization
- cmake: use the standard variable CMAKE_BUILD_TYPE instead of
  DEVEL_MODE

Release 1.16.0

- [API Change] Add lsquic_conn_n_avail_streams()
- [BUGFIX] only dispatch crypto stream read events if WANT_READ is on

Minor API change and a bug fix

Release 1.15.0

- [API Change] Add LSCONN_ST_PEER_GOING_AWAY to the list of conn statuses
- [BUGFIX] free uncompressed headers correctly when error occurs

Bugfix release

• [BUGFIX] Do not abort conn on STREAM frame for a reset stream
• [BUGFIX] Drop packets that would become empty due to repackaging.
  Packets on the scheduled queue may be marked for repackaging.
  Frames such as ACK frame that are never resent are removed from
  repackaged packets. We must check that the newly repackaged packet
  would not be empty. If it would be, it is destroyed instead and
  the next packet on the scheduled queue is used. Note that this
  change only affects the logic to return the next packet to be sent.
  Lost packets that are being rescheduled are already processed in
  this fashion.
• Byteswap CID before logging it - this makes it match Chrome CIDs.
  (Except Q035, which is the last little-endian GQUIC version we
  support.)

API Change, Bug Fixes

Release 1.14.0

- [API Change] Disable packet sending if full batch cannot be sent
  If lsquic_packets_out_f() cannot send the whole batch, disable
  packet sending until lsquic_engine_send_unsent_packets() is called.
- [BUGFIX] Handle case when STREAM frame does not fit.
- [BUGFIX] Always allow incoming STREAM frames to overlap.  Peers
  may send overlapping STREAM frames even if using versions older
  than Q043.
- Custom header set fixes:
  - set "FIN reached" flag when custom header with FIN flag is
    claimed;
  - do not return custom header set for a reset stream.

[FEATURE, API Change] HTTP header bypass

1.13.0: [FEATURE, API Change] HTTP header bypass

Add ability to create custom header set objects via callbacks.
This avoids reading and re-parsing headers from the stream.

See test/http_client.c for example implementation.  (Use -B flag
to turn it on).

Fix memory leaks

1.12.4

1.12.4: Fix memory leaks and gcc compilation warnings

[BUGFIX] Fix duplicate STREAM frame detection

1.12.3

1.12.3: [BUGFIX] Fix duplicate STREAM frame detection

Bugfix release

1.12.2

1.12.2: Bugfix and log message improvements