docker/machine 0.0.2 (new formula)

The tool is in alpha and for now I'm only packaging the pre-built binary.
Can a test be added to do something more substantial than e.g. `--version` or `--help`? See `cmake.rb` for an example of an application formula with a good test and `tinyxml2.rb` for an example of a library formula with a good test. Thanks!