fixes #154

Lets the user stop the install if cancel is selected.

automated install/basic-install.sh

@@ -103,6 +103,7 @@ In the next section, you can choose to use your current network settings (DHCP)
 chooseInterface()
 {
 # Turn the available interfaces into an array so it can be used with a whiptail dialog
+if [[ $chooseInterfaceOptions ]];then
 	interfacesArray=()
 	firstloop=1
 
@@ -115,7 +116,11 @@ if [[ $firstloop -eq 1 ]]; then
 		fi
 		interfacesArray+=("$line" "available" "$mode")
 	done <<< "$availableInterfaces"
-
+else
+	# Exit if user cancels
+	echo "Cancelling installation."
+	exit
+fi
 # Find out how many interfaces are available to choose from
 interfaceCount=$(echo "$availableInterfaces" | wc -l)
 chooseInterfaceCmd=(whiptail --separate-output --radiolist "Choose An Interface" $r $c $interfaceCount)
@@ -135,6 +140,7 @@ cmd=(whiptail --separate-output --checklist "Select Protocols" $r $c 2)
 options=(IPv4 "Block ads over IPv4" on
          IPv6 "Block ads over IPv6" off)
 choices=$("${cmd[@]}" "${options[@]}" 2>&1 >/dev/tty)
+if [[ $choices ]];then
 for choice in $choices
 do
     case $choice in
@@ -142,6 +148,11 @@ do
         IPv6)useIPv6=true;;
     esac
 done
+else
+	# Exit if user cancels
+	echo "Cancelling installation."
+	exit
+fi
     if [ $useIPv4 ] && [ ! $useIPv6 ]; then
      	getStaticIPv4Settings
 			setStaticIPv4