We want to specify a security group name, but we have to use an ID.

Auto-create the 'blocked' security, unless it already exists.  Map it to an ID.
Merge branch 'block_network_chaos_type'

Conflicts:
	src/main/java/com/netflix/simianarmy/CloudClient.java
	src/main/java/com/netflix/simianarmy/client/aws/AWSClient.java