Retry starting Instances

[anson-git]

Main changes on this PR:

• Only generate the instrumented files (call istanbul plugin) when NODE_ENV=test.
• Bump the version of aws-sdk, aws-sdk-mock, serverless, nodejs.
• Resolve always reporting "All EC2, RDS instances, ASGs, and ECS services started successfully. Good morning!", even though a certain function fail to complete.
• Add a new function to auto retry starting the instances, until a maxAttempts is reached.