add files to define missing functions (snprintf and strtod)
add windows specific thread files
use ffmpeg generated config.h file + desactive some unnecessary flags for correct compilation
disable yasm files
remove temporary SSE functions
remove forcing external prefix for snprintf and strtod for correct compilation on 32bits
add avpriv_snprintf directly to file since include is not possible (to be cleaned later)
remove miscellaneous commands incompatible with msvc compilation
add sse4 and sse3 headers and compile SSE functions (OK for x64) to be updated to match x86
remove SSE4 and SSE3 headers and let visual use native functions
active SSE4 functions
(cmake) set default SSE4 and SSE3 flags to true
active yasm functions to enable SSE in 64bits (32 bits turns to KO)
Generic solution to enable SSE with x64 and disable it with x86 (see definition in Cmakelists file)
Merge branch 'hevc' into hevc_msvc

Conflicts:
	libavcodec/x86/hevc_idct_sse4.c
	libavcodec/x86/hevc_il_pred_sse.c
	libavcodec/x86/hevc_intra_pred_sse.c
	libavcodec/x86/hevc_mc_sse.c
	libavcodec/x86/hevc_sao_sse.c
	libavcodec/x86/hevcdsp_init.c
	libavcodec/x86/hevcpred_init.c
comment unlinked functions (loop_filter_luma_SSE3 and chroma_SSE2 10)
fix bad merge with asm deblk.asm file
merge with hevc
merge with all ffmpeg files
add .mkv, .mp4 and .ts format
clean