installation script for OS Devuan (#95)

* adding devuan

* add devaun desc to README
make update and upgrade more noisy
correct path for devuan in pre-install

* some untested code for the source install - source installation is broken in Debian installation script and I have not debugged the problem. Focusing on the packaged version first.

devuan/resources/sngrep.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+#move to script directory so all relative paths work
+cd "$(dirname "$0")"
+
+#includes
+. ./config.sh
+. ./colors.sh
+. ./environment.sh
+
+#add sngrep
+if [ ."$cpu_architecture" = ."arm" ]; then
+	#source install
+	apt-get -q -y install git autoconf automake gcc make libncurses5-dev libpcap-dev libssl-dev libpcre3-dev
+	cd /usr/src && git clone https://github.com/irontec/sngrep
+	cd /usr/src/sngrep && ./bootstrap.sh
+	cd /usr/src/sngrep && ./configure
+	cd /usr/src/sngrep && make install
+else
+	#package install
+	echo 'deb http://packages.irontec.com/debian jessie main' > /etc/apt/sources.list.d/sngrep.list
+	wget http://packages.irontec.com/public.key -q -O - | apt-key add -
+	apt-get -q update
+	apt-get -y -q install sngrep
+fi