Miscellaneous fixes

[bennylp]

(In [3836]) Misc (re #1393): increase default H.263 bandwidth

[nanang]

(In [3838]) Misc (re #1393): Put log warning in ffmpeg codecs when a codec is enabled but cannot be found in ffmpeg library.

[bennylp]

(In [3839]) Misc (re #1393): fixed wrong libavutil version detection

[bennylp]

(In [3852]) Misc (re #1393): crash in vid win command without argument

[nanang]

(In [3857]) Misc (re #1393): cosmetic in call dump, missing '=' char in avg bitrate in TX :)

[bennylp]

(In [3866]) Re #1393 (misc): remove unnecessary call to start preview renderer in video update

[bennylp]

in r3870: added info about ICE candidates being used (both local and remote) in pjsua dump call output

[bennylp]

(In [3874]) Misc (re #1393): disable jbuf tracing

[bennylp]

(In [3875]) Misc (re #1393): write log if adding pjsua buddy fails

[bennylp]

(In [3887]) Missing video component deinitialization caused assertion when the stack is restarted. Thanks Régis Montoya for the report (re #1393)

[bennylp]

(In [3890]) Fixed problem with selecting audio codec if rtpmap is omitted from the SDP for the static PT (re #1393, thanks Régis Montoya for the fix!)

[nanang]

(In [3892]) Misc (re #1393): fix linking error "app_config_init_video() not found" when video is disabled, also some compile warnings (unused variables).

[bennylp]

(In [3894]) Minor (re #1393): fixed compilation warning in pjsua app if video is disabled

[nanang]

(In [3909]) Misc (re #1393): fix compile error in pjsua_media.c (undefined member 'bitrate' in struct 'pjmedia_format') when using passthrough codec.

[nanang]

(In [3910]) Misc (re #1393): fix compile error in pjmedia-codec/audio_codecs.c, caused by typo and wrong member reference: '&c->passthough.ilbc' should be '&c->passthrough.setting'.

[nanang]

(In [3917]) Misc (re #1393): fix bitrate calculation in stream.c and wav_playlist.c.

[bennylp]

(In [3921]) Re #1393 (misc): renamed label on_error to on_return and fixed warning re constness

[bennylp]

(In [3922]) Re #1393 (misc): reduced default ffmpeg h264 bandwidth from 512 to 256kbps

[bennylp]

(In [3923]) Misc (re #1393): vidgui: added account and NAT support and fixed assertion on incoming call

[bennylp]

(In [3926]) Re #1393: added checkbox to enable/disable video in vidgui sample app

[bennylp]

(In [3927]) re #1393: error in detecting libavformat in mac os if ffmpeg was built and libbzip2-dev is installed. This caused ffmpeg to be built with dependency to libbz2, while our configure does not, causing link error during libavformat detection. This is temporarily fixed by adding libbz2 detection in aconfigure.ac

[nanang]

(In [3930]) Misc (re #1393): vidgui: fixed zombie video window after re-INVITE by always destroying any incoming video window first before processing media update.