OSX Install: DEPRECATED Action signature

Installing on MacOSX Yosemite (10.10.5)

`go-thrust install`

```
DEPRECATED Action signature.  Must be `cli.ActionFunc`. 
 This is an error in the application.  Please contact the distributor of this application if this is not you.  See https://github.com/urfave/cli/blob/master/CHANGELOG.md#deprecated-cli-app-action-signature
```
