Fixes to rb-fsevent issues on heroku

@whitschrader

a) Keep your gemfiles clean. I've cleaned it up for you majorly. Make sure that you understand how I've cleaned it up and please ask any questions in the pull request comments below.
b) Read http://www.johnplummer.com/rails/heroku-error-conditional-rbfsevent-gem.html for the fix I had implemented. Read it fully, and understand exactly what the author wrote.

Btw, my search query for the above article was:

```
heroku you have deleted from the gemfile rb-fsevent
```

@rsofaer: any additional comments?