[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/gmenu2x/sections/applications/ffplay.launch

@@ -0,0 +1,5 @@
+title=FFPLAY
+description=Play a movie/audio file
+exec=/mnt/apps/ffmpeg/ffplay_launch.sh
+manual=/mnt/apps/ffmpeg/manual.txt
+selectordir=/mnt/output

board/miyoo/main/gmenu2x/sections/applications/record-audio

@@ -0,0 +1,4 @@
+title=AUDIO rec
+description=Start/Stop recording alsa HW audio output
+exec=/mnt/apps/arecord/audio_record.sh
+params=&

board/miyoo/main/gmenu2x/sections/applications/record-video

@@ -0,0 +1,4 @@
+title=VIDEO Rec
+description=Start/Stop recording FB0 video in the background
+exec=/mnt/apps/ffmpeg/video_record.sh
+params=&

board/miyoo/main/gmenu2x/sections/applications/usb-change_primary_partition

@@ -1,3 +0,0 @@
-title=USB change part.
-description=USB switch FAT partition
-exec=/mnt/apps/usb-serial-mass-storage/usb-change_primary_partition.sh