calabash-android should support opening a console that loads a custom .irbrc

## Motivation

It is handy to be able to load the project page models, data models, and helper modules into the irb; it helps with exploring the app and debugging steps.

## Testing

I did some smoke testing on some of the internal Xamarin projects and things appear to work.

## Other

Updated the `.gitignore` to support emacs and rbenv dev environments.