New setup script

- No longer installs numpy and scipy because they are preinstalled on
the current Spark AMI
- Set paths and aliases for Thunder
- Create Thunder egg and set a path for it
Commit of Thunder EC2 script

- Executable and associated Python script to launch a Spark cluster on
EC2 and install Thunder
- This is a wrapper for the Spark EC2 deploy script, using its methods
and classes where possible, but adding additional functionality in
places (e.g. installing Thunder, copying an example dataset into HDFS)