[BOARD/PACKAGE] add FFMPEG to record&play /dev/fb0 + alsa capture (#48)

* [PACKAGE] downgrade FFMPEG(add) & X264
- use ffmpeg-3.1 thus downgrade ver. to working SDL1.2
- downgrade x264 to be inline with former ffmpeg
- uncomment FFSERVER build instructions (it is available in 3.1 version)

* [BOARD] 
- add `ffplay` & `ffmpeg` apps to record&play
- add `arecord` script for AUDIO capture (use alsaloop workaround)
- update appLinks with "params=&" for bg launch
- use `pkill` instead 'killall` for scripts (warning: it also checks for bash running under the same name)
- use FFPROBE to detect media format in `ffplay`
- for X264  use sources.buildroot.net (code.videolan.org src only works with git method)
- rm redundant usb Applink
- add 0003-ffplay-custom-sdlk.patch (to make hotkeys usable in miyoo)

board/miyoo/main/apps/ffmpeg/ffplay_launch.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+if ffprobe -v error -select_streams v:0 -show_entries stream=codec_type "$1" | grep -q "video"; then
+	ffplay -autoexit -i "$1"
+elif ffprobe -v error -select_streams a:0 -show_entries stream=codec_type "$1" | grep -q "audio"; then
+	ffplay -nodisp -autoexit -i "$1"
+else
+	echo -en "Invalid video/audio format!"
+	# We're using SDL terminal to display above echo msg 
+	## because all stdout is parsed to /dev/null from gmenu2x and it's child ps
+	/mnt/apps/st/st -e "/bin/sh" "-c" "echo -e \"\n\n\n\n\n\n          Invalid video or audio format!\"; sleep 2"
+fi