Inquirer

New feature
- `inquirer.createPromptModule(opt)` not take an `option` arguments. These [options will be passed to the readline factory](https://nodejs.org/api/readline.html#readline_readline_createinterface_options).

Bug fix
- Fix 276 and 209: adding a new observer to the process won't duplicate the prompts (basically the prompt processing queue is now a [hot observable](https://github.com/Reactive-Extensions/RxJS/blob/master/doc/gettingstarted/creating.md#cold-vs-hot-observables)).

1. Fix a lot of issues with natural line returns messing inquirer.js prompt re-rendering.
2. The `validate` function now takes the list of current answers as arguments. 198

This is not a huge release feature wise. It's been mostly a huge internal refactoring of our rendering system. This is all done with the hope of moving towards a 1.0 release where we'll have a stronger Prompt API allowing the creation of custom prompts.

Fix issue with cursor position in the `input` prompt.

- More consistent handling of the checkboxes checked param if the value is truthy (before the option would be checked but not selected) - 242

- `when` prompt option can now simply be a boolean value (before it needed to be a function).