set HDMI EDID before starting ustreamer (#179)

* build docker image

* Push each image to an user github registry.
It can be used during development for testing.

* set HDMI EDID before starting ustreamer

* Update README.md

pkg/docker/entry.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+set -e
+
+[ -z "$NO_EDID" ] && {
+	[ -n "$EDID_HEX" ] && echo "$EDID_HEX" > /edid.hex
+	while true; do
+		v4l2-ctl --device=/dev/video0 --set-edid=file=/edid.hex --fix-edid-checksums --info-edid && break
+		echo 'Failed to set EDID. Reetrying...'
+		sleep 1
+	done
+}
+
+./ustreamer --host=0.0.0.0 $@