closes #24 whitelist without running gravity.sh

It's pretty slow because /etc/hosts is so large, but it works.  You can
add any number of domains as arguments and it will search for and
remove each one.

Maybe someone smarter knows how to make it faster...

advanced/Scripts/whitelist.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+# For each argument passed to this script
+for var in "$@"
+do
+        echo "Whitelisting $var..."
+        # Use sed to search for the domain in /etc/hosts and remove it using an in-place edit
+        sed -i "/$var/d" /etc/hosts
+        # Also add the domain to the whitelist.txt in /etc/pihole
+        echo "$var" >> /etc/pihole/whitelist.txt
+done
+echo "** $# domain(s) whitelisted."
+# Force dnsmasq to reload /etc/hosts
+kill -HUP $(pidof dnsmasq)