Commiting changeset for new EC2 rule to warn on potentially unscannable ...

This pull requests represents a feature enhancement to Scout2 that reports on any AWS EC2 instances that may not be scannable based on Amazon's rules of engagement for penetration testing. Currently, the t1.micro and m1.small instance types cannot be tested based on AWS policy. Note: the set of "no-test" instances is configurable in the new rule's definition. To turn off this rule, simply leave the list of instances empty.