Merge remote branch 'qatar/master'

* qatar/master:
  drawtext: add documentation for the shadow parameters
  drawtext: add shadow support.
  drawtext: factor draw_glyphs.
  drawtext: fix and optimize yuv blend.
  drawtext: get rid of divisions in the inner loop.
  drawtext: simplify chroma blend and fix chroma alpha.
  lavfi: Port drawtext filter by Hemanth from the libavfilter soc repo

Conflicts:
	configure
	libavfilter/avfilter.h
	libavfilter/vf_drawtext.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -2905,7 +2905,7 @@ enabled libdirac   && require_pkg_config dirac                          \
     "libdirac_decoder/dirac_parser.h libdirac_encoder/dirac_encoder.h"  \
     "dirac_decoder_init dirac_encoder_init"
 enabled libfaac    && require2 libfaac "stdint.h faac.h" faacEncGetVersion -lfaac
-enabled libfreetype && add_cflags $(pkg-config --cflags freetype2) && require libfreetype ft2build.h FT_Init_FreeType -lfreetype
+enabled libfreetype && require_pkg_config freetype2 "ft2build.h freetype/freetype.h" FT_Init_FreeType
 enabled libgsm     && require  libgsm gsm/gsm.h gsm_create -lgsm
 enabled libmp3lame && require  "libmp3lame >= 3.98.3" lame/lame.h lame_set_VBR_quality -lmp3lame
 enabled libnut     && require  libnut libnut.h nut_demuxer_init -lnut