h264: Refactor ff_h264_decode_ref_pic_list_reordering

In preparation for MVC support.
h264: print values in case of error

Also make error style consistent and drop redundant information.
h264: store current_sps_id inside the current sps

In preparation for MVC support.
h264: drop outdated comments
h264_sei: name buffering period type consistently
h264_sei: reorder headers

Also drop unused assert.h.
Doxyfile: Only set HTML_{HEADER|FOOTER|STYLESHEET} from doxy_wrapper.sh
build: Do not pass HTML snippets and stylesheet as input to Doxygen

These files are referenced elsewhere and only generate warnings if
presented to Doxygen as input files.
doxygen: Set EXAMPLE_PATH from within doxy-wrapper.sh

This allows using the libav source path as the example path.
build: doxy: Include code examples in Doxygen documentation
doc/examples: misc Doxygen markup improvements

Add properly formatted @example tag and fix Doxygen syntax.
Merge commit 'f8c507f44b4c994895fc7ad954f009f61de69b1c'

* commit 'f8c507f44b4c994895fc7ad954f009f61de69b1c':
  h264: Refactor ff_h264_decode_ref_pic_list_reordering

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '73e8fab31dc19c4371499e612856accbc00b2820'

* commit '73e8fab31dc19c4371499e612856accbc00b2820':
  h264: print values in case of error

Conflicts:
	libavcodec/h264.c
	libavcodec/h264_ps.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '3a0576702825423abecb32627c530dbc4c0f73bc'

* commit '3a0576702825423abecb32627c530dbc4c0f73bc':
  h264: store current_sps_id inside the current sps

Conflicts:
	libavcodec/h264.c
	libavcodec/h264_ps.c

The current_sps_id is not removed as it used in security related code.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '15210354cf27cf4e24d91f84d66cf471511ce718'

* commit '15210354cf27cf4e24d91f84d66cf471511ce718':
  h264: drop outdated comments

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '304e916a92bc17385a485bec2f957e192257ddb6'

* commit '304e916a92bc17385a485bec2f957e192257ddb6':
  h264_sei: name buffering period type consistently

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '066ad249843bde656265b59110c2521e2b1ce131'

* commit '066ad249843bde656265b59110c2521e2b1ce131':
  h264_sei: reorder headers

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'e6c175dfd51e4b0e6deeae72cd8a161b22af3492'

* commit 'e6c175dfd51e4b0e6deeae72cd8a161b22af3492':
  Doxyfile: Only set HTML_{HEADER|FOOTER|STYLESHEET} from doxy_wrapper.sh

Conflicts:
	doc/Doxyfile

See: 7d0ca5b7e43676cc23834ccd19d40744f7328b77
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'f1f42cfc66804907d1df9231469e4296472bb0f5'

* commit 'f1f42cfc66804907d1df9231469e4296472bb0f5':
  build: Do not pass HTML snippets and stylesheet as input to Doxygen

Conflicts:
	doc/Makefile

See: 0f378d86321e4d14153a28d5e74c3ff0f99b1a20
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '19d3127867f001d007f98bc8c5a85c5409abf788'

* commit '19d3127867f001d007f98bc8c5a85c5409abf788':
  doxygen: Set EXAMPLE_PATH from within doxy-wrapper.sh

Conflicts:
	doc/Doxyfile
	doc/doxy-wrapper.sh

Merged-by: Michael Niedermayer <michaelni@gmx.at>