- rework terminate() and idleTimeout() so that the Amazon instructions are in indepdendent
methods stop() and terminateInstance()
- terminate() falls back to stop() if the termination command fails; this to ensure that the EC2
instance is stopped in case the instance has termination protection on it, as it is observed
that EC2 will provision an existing stopped/termination-protected instance in some cases
Merge branch 'terminate_fallback'

Conflicts:
	src/main/java/hudson/plugins/ec2/EC2Slave.java
Merge pull request #33 from zzzeek/master

fallback a manual or timeout-based terminate to stop if terminate fails