Add stop action from spark_ec2. Also add TODOs.
Update doc for passwd hint.
Clarifications in doc; update TODOs.
Automatic whitespace fixes & add TODOs.
Update to Ambari 1.6.0 repo URL.
Comment out an un-used variable.
Completely automate setup_ambari_master().
Update TODOs.  Also install screen on all nodes during cluster setup.
Update notes.
Line-separate a long command.
Comment out prepare_tez() entirely.

Because Ambari already ships with Tez. Note some configs may be worth
re-visiting.
Add missing run query example for Hive/Tez in index.md.
Fix hive runner prefix: remove stinger settings, use hdfs as username.
Fix IOError (dir might not exist).
Port spark-ec2 scripts & related files from Spark upstream.

These will probably be used to launch a Spark-only (no Hive/Tez)
cluster.
Add deploy.generic.hdp, used for Spark deployment on HDP.
Add skeleton port of Spark installation support (commented out for now).
Set master type correctly when launching spot.
Bumping Ambari to 1.6.1 (for Redhat/CentOS/Oracle only). Not tested.
Support for launching r3 spot instances on SLES AMI.