better uninstall

More from JoshKastang.  This closes #153 as it is the last step from
his ideas.

automated install/uninstall.sh

@@ -8,20 +8,57 @@
 # the Free Software Foundation, either version 2 of the License, or
 # (at your option) any later version.
 
+# Must be root to uninstall
+if [[ $EUID -eq 0 ]];then
+	echo "You are root."
+else
+	echo "sudo will be used for the install."
+	export SUDO="sudo"
+fi
+
 
 ######### SCRIPT ###########
-sudo apt-get -y remove --purge dnsutils bc toilet
-sudo apt-get -y remove --purge dnsmasq
-sudo apt-get -y remove --purge lighttpd php5-common php5-cgi php5
-sudo rm -rf /var/www/html
-sudo rm /etc/dnsmasq.conf /etc/dnsmasq.conf.orig
-sudo rm /etc/crontab
-sudo mv /etc/crontab.orig /etc/crontab
-sudo rm /etc/dnsmasq.conf
-sudo rm -rf /etc/lighttpd/
-sudo rm /var/log/pihole.log
-sudo rm /usr/local/bin/gravity.sh
-sudo rm /usr/local/bin/chronometer.sh
-sudo rm /usr/local/bin/whitelist.sh
-sudo rm /usr/local/bin/piholeLogFlush.sh
-sudo rm -rf /etc/pihole/
+$SUDO apt-get -y remove --purge dnsutils bc toilet
+$SUDO apt-get -y remove --purge dnsmasq
+$SUDO apt-get -y remove --purge lighttpd php5-common php5-cgi php5
+
+# Only web directories/files that are created by pihole should be removed.
+echo "Removing the Pi-hole Web server files..."
+$SUDO rm -rf /var/www/html/admin
+$SUDO rm -rf /var/www/html/pihole
+$SUDO rm /var/www/html/index.lighttpd.orig
+
+# If the web directory is empty after removing these files, then the parent html folder can be removed.
+if [[ ! "$(ls -A /var/www/html)" ]]; then
+    $SUDO rm -rf /var/www/html
+fi
+
+echo "Removing dnsmasq config files..."
+$SUDO rm /etc/dnsmasq.conf /etc/dnsmasq.conf.orig
+
+# Attempt to preserve backwards compatibility with older versions
+# to guarantee no additional changes were made to /etc/crontab after
+# the installation of pihole, /etc/crontab.pihole should be permanently
+# preserved.
+if [[ -f /etc/crontab.orig ]]; then
+  echo "Initial Pi-hole cron detected.  Restoring the default system cron..."
+	$SUDO mv /etc/crontab /etc/crontab.pihole
+	$SUDO mv /etc/crontab.orig /etc/crontab
+	$SUDO service cron restart
+fi
+
+# Attempt to preserve backwards compatibility with older versions
+if [[ -f /etc/cron.d/pihole ]];then
+  echo "Removing cron.d/pihole..."
+	$SUDO rm /etc/cron.d/pihole
+fi
+
+echo "Removing config files and scripts..."
+$SUDO rm /etc/dnsmasq.conf
+$SUDO rm -rf /etc/lighttpd/
+$SUDO rm /var/log/pihole.log
+$SUDO rm /usr/local/bin/gravity.sh
+$SUDO rm /usr/local/bin/chronometer.sh
+$SUDO rm /usr/local/bin/whitelist.sh
+$SUDO rm /usr/local/bin/piholeLogFlush.sh
+$SUDO rm -rf /etc/pihole/