vsrc_testsrc: switch to an AVOptions-based system.
lavfi: remove now unused args parameter from AVFilter.init
lavfi: error out when options are provided to a filter that does not take any
lavfi: make AVFilterContext export filter options.
lavfi: add avfilter_get_class().

Useful for examining options, the same as the corresponding functions
for the other libs.
Merge commit '7b3eb745b98b04dd8a4970b9fd6c98998e858fc1'

* commit '7b3eb745b98b04dd8a4970b9fd6c98998e858fc1':
  vsrc_testsrc: switch to an AVOptions-based system.

Conflicts:
	doc/filters.texi
	libavfilter/vsrc_testsrc.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'c43a7ecad997fc527af34b952334f3d030709a1b'

* commit 'c43a7ecad997fc527af34b952334f3d030709a1b':
  lavfi: remove now unused args parameter from AVFilter.init

Conflicts:
	libavfilter/avfilter.c
	libavfilter/buffersrc.c
	libavfilter/f_select.c
	libavfilter/src_movie.c
	libavfilter/vf_alphamerge.c
	libavfilter/vf_drawtext.c
	libavfilter/vf_lut.c

Not merged (yet) because there are still many filters that use the args
parameter.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '62549f9655c48f0ec061087fa33a96040ce01145'

* commit '62549f9655c48f0ec061087fa33a96040ce01145':
  lavfi: error out when options are provided to a filter that does not take any

Conflicts:
	libavfilter/avfilter.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '4d1f31ea44f82adfb2b712534d71e27233a4f785'

* commit '4d1f31ea44f82adfb2b712534d71e27233a4f785':
  lavfi: make AVFilterContext export filter options.

Conflicts:
	libavfilter/avfilter.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
lavfi: restore mixed short/long option support with the new system.

process_unnamed_options() is renamed to process_options() and its code
is heavily based on av_opt_set_from_string().
Merge commit '8114c101607843a86960bd3e0e9c40487dc2a961'

* commit '8114c101607843a86960bd3e0e9c40487dc2a961':
  lavfi: add avfilter_get_class().

Conflicts:
	libavfilter/avfilter.h

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'ubitux/lavfi-mixed-short-long'

* ubitux/lavfi-mixed-short-long:
  lavfi: restore mixed short/long option support with the new system.

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