Fixes issue #2 whitelist support

Just put a file named whitelist.txt in your home folder.  This file
should contain one domain per line that needs to be whitelisted.  If
the file does not exists, the script will continue as normal.

gravity-adv.sh

@@ -7,6 +7,7 @@ piholeIP="127.0.0.1"
 
 # Config file to hold URL rules
 eventHorizion="/etc/dnsmasq.d/adList.conf"
+whitelist=$HOME/whitelist.txt
 
 echo "Getting yoyo ad list..." # Approximately 2452 domains at the time of writing
 curl -s -d mimetype=plaintext -d hostformat=unixhosts http://pgl.yoyo.org/adservers/serverlist.php? | sort > /tmp/matter.txt
@@ -26,12 +27,20 @@ echo "Getting Mother of All Ad Blocks list..." # 102168 domains!! Thanks Kacy
 curl -A 'Mozilla/5.0 (X11; Linux x86_64; rv:30.0) Gecko/20100101 Firefox/30.0' -e http://forum.xda-developers.com/ http://adblock.mahakala.is/ | grep -v "#" | awk '{print $2}' | sort >> /tmp/matter.txt
 
 # Sort the aggregated results and remove any duplicates
-echo "Removing duplicates and formatting to address=/<ad domain>/"$piholeIP
-cat /tmp/matter.txt | sed $'s/\r$//' | sort | uniq | sed '/^$/d' | awk -v "IP=$piholeIP" '{sub(/\r$/,""); print "address=/"$0"/"IP}' > /tmp/andLight.txt
+# Remove entries from the whitelist file if it exists at the root of the current user's home folder
+if [[ -f $whitelist ]];then
+	echo "Removing duplicates, whitelisting, and formatting the list of domains..."
+	cat /tmp/matter.txt | sed $'s/\r$//' | sort | uniq | sed '/^$/d' | grep -v -x -f $whitelist | awk -v "IP=$piholeIP" '{sub(/\r$/,""); print "address=/"$0"/"IP}' > /tmp/andLight.txt
+	numberOfSitesWhitelisted=$(cat $whitelist | wc -l | sed 's/^[ \t]*//')
+	echo "$numberOfSitesWhitelisted domains whitelisted."
+else
+	echo "Removing duplicates and formatting the list of domains..."
+	cat /tmp/matter.txt | sed $'s/\r$//' | sort | uniq | sed '/^$/d' | awk -v "IP=$piholeIP" '{sub(/\r$/,""); print "address=/"$0"/"IP}' > /tmp/andLight.txt
+fi
 
-# Count how many domains were added so it can be displayed to the user
+# Count how many domains/whitelists were added so it can be displayed to the user
 numberOfAdsBlocked=$(cat /tmp/andLight.txt | wc -l | sed 's/^[ \t]*//')
-echo "$numberOfAdsBlocked ad domains added to the blacklist"
+echo "$numberOfAdsBlocked ad domains blocked."
 
 # Turn the file into a dnsmasq config file
 mv /tmp/andLight.txt $eventHorizion