Relay information about why instances aren't booted up: instance limits vs. not enough capacity vs. internal code error

[mcianfrocco]

Need a better system to give user feedback if/when jobs don't launch using awslaunch. Possible scenarios:

-AWS is at capacity - no more instances available
-> If this is the case, try to launch in different AZ?
-AMI does not exist (code error)
-User does not have limit increase for using instance