genie 2.8.0 (new formula)

### GENIE

GENIE (Generates Events for Neutrino Interaction Experiments) is a universal object-oriented neutrino MC generator

More info: http://genie.hepforge.org

### Install Instructions

```bash
brew install https://raw.githubusercontent.com/fiedl/homebrew-hep/fiedl/genie/genie.rb

# or, after merging this pull request:
brew tap davidchall/hep
brew update
brew install genie
```

### Tested

I successfully installed genie through this package on Mac OS X 10.9.3, including its dependencies. But, maybe someone could test this on a clean machine?