libavsmash: Set 0 to the end of the additional FF_INPUT_BUFFER_PADDING_SIZE bytes.

Without this, some decoders could cause wrong results.
lsmashsource: Add 'rate' option to specify output audio sample rate.
exlibs: Move libmingwex.a from MSVC project to.
lwlibav: Do pre-rolling if audio frame has lossy property.
lsmashinput: Change the layout of the settings dialog.
lsmashinput: Change INPUT_PLUGIN_TABLE slightly.
lsmashmuxer: Change the name of this plugin.
lsmashdumper: Change the name of this plugin.
lsmashinput: Add 'sampling rate' settings.

The default value 0 means the output sampling rate will be the maximum sampling rate in the stream.
libavsmash: Fix the calculation of the number of decoded PCM audio samples which shall be skipped.
lwlibav: Fix average displayed framerate caluclation when PTSs are generated.
configure: Fix permissions.
libavsmash: Fix resampling the number of PCM audio samples when no start offset.
Merge branch 'plain' into build-msvc

Merge revision: r520
Conflicts:
	AviUtl/libav_input.c
	AviUtl/libavsmash_input.c
	common/libavsmash_audio.c
	common/lwindex.c
	common/lwlibav_audio.c
	common/lwlibav_video.c