update readme

apache-spark/README.md

-## Prerequisites:
+# Prerequisites:
 
-# Java 7+ installed on master & slave machines
-# Scala 2+ installed on master & slave machines
-# PySpark installed on master machine (`sudo pip install pyspark`)
-# apache-spark project & streaming files cloned on each slave machine 
+### Java 7+ installed on master & slave machines
+### Scala 2+ installed on master & slave machines
+### PySpark installed on master machine (`sudo pip install pyspark`)
+### apache-spark project & streaming files cloned on each slave machine 
 
-## Start up Spark cluster
+# Start up Spark cluster
 
 ```
 ./sbin/start-all.sh
 ```
 
-# This starts up VMs 2-10 as worker machines, cluster summary can be seen on http://MASTER-IP:8080/
+### This starts up VMs 2-10 as worker machines, cluster summary can be seen on http://MASTER-IP:8080/
 
-## Submit a word count job to the cluster 
+# Submit a word count job to the cluster 
 
 ```
 bin/spark-submit --master spark://MASTER-IP:7077 --deploy-mode client ~/apache-spark/python/wordcount.py ~/apache-spark/python/higgs-activity_time.txt
 ```
 
-# Job summary can be seen on http://MASTER-IP:4040/
+### Job summary can be seen on http://MASTER-IP:4040/
 
-# Notes:	
+## Notes:	
 	
-# 1. spark-env.sh file within conf/ should be modified as per job & master/slave requirements 
-# 2. /etc/hosts file on master & slave should have IP addresses resolved to the same hostnames within the slaves file in conf/
-# 3. Project includes setup scripts/examples/driver code from Apache Spark
+### 1. `spark-env.sh` file within `conf/` should be modified as per job & master/slave requirements 
+### 2. `/etc/hosts` file on master & slave should have IP addresses resolved to the same hostnames within the slaves file in `conf/`
+### 3. Project includes setup scripts/examples/driver code from Apache Spark (https://github.com/apache/spark)