Split Destroy/Terminate actors. Add problem checking.

I suggest squashing the commits since I know that they are slightly disorganized, and the commit messages don't always describe what's been done. Main changes are obviously:

* Separate responsibilities into Terminate and Destroy actors.
* Create `find_problems` actor method to detect issues before execution.
This logic isn't right. You can run scripts that are not associated with a server template in RightScal. This check though requires that the script be associated with the template, or it will not find the input names.

You should be getting the right script or recipe and checking the required inputs of that object.