[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)

package/x264/x264.hash

@@ -1,3 +1,2 @@
 # Locally computed
-sha256  58f39bf23a4e38ac3dd841a3f9ccf2aa16d2b0c35df9aecd9f3b5062780e5d74  x264-35417dcd65a57321fbadf98c9a4cff1cb741db4b.tar.gz
-sha256  32b1062f7da84967e7019d01ab805935caa7ab7321a7ced0e30ebe75e5df1670  COPYING
+sha256  a3a304da9eb1d5e6b19102e3c4156e17a9e7142d6dc1336e1001ff214c986843  x264-72d53ab2ac7af24597a824e868f2ef363a22f5d4.tar.gz