Add support ec2 instances

[groorj]

Hi Ville Seppänen,

I added support to EC2 instances termination. Please take a look at the code at your earliest convenience and let me know what you think.

Thanks, Gustavo

[rasathus]

Hi @groorj , I stumbled across this change whilst looking at your fork. I was surprised to find the functionality, as there isn't an entry in the config example. After digging a little deeper I think I have discovered why.

It looks as if this new addition is inconsistent with the rest of the project in that it doesn't offer and or observe the 'preserve' list. I'd suggest this is a somewhat dangerous inconsistency, as it could result in unexpected behaviour. My personal recommendation would be to rework this to observe the same preserve list structure as the rest of the services.