Create a utility to check for remote executable availability

It will properly inform a user if the executable is not available (as opposed to crashing with subprocess later on)

![screen shot 2014-07-08 at 10 13 56 am](https://cloud.githubusercontent.com/assets/317847/3510818/231e0dde-06aa-11e4-88ee-8faefa08e671.png)

"on {host}" is better grammar