WIP - Rename event and hangout models

## This is work in progress
__The reason why I'm submitting a PR that is not ready to be merged in is because I'm pretty much stuck.__

PT Chore: https://www.pivotaltracker.com/story/show/78137634
- changed the name of the Controller and the associated Model, Views, Helpers, Tests & Routes directories, file names, class names & the names in the class definitions from `Hangout` -> `EventInstance`
- created a migration to change the table name (database level). 

The current status is that __ALL__ specs and jasmine test are passing <font color='green'>__GREEN__ </font>(even the viewspecs for `events/show`). Cucumber is a different story:

   ```
Failing Scenarios:
cucumber features/hangout.feature:30 # Scenario: Show hangout details
cucumber features/hangout.feature:47 # Scenario: Show restart hangout
cucumber features/hangout.feature:56 # Scenario: Restart hangout
cucumber features/hangout.feature:86 # Scenario: Render Join live event link
cucumber features/hangout.feature:105 # Scenario: Display live sessions - basic info
cucumber features/hangout.feature:138 # Scenario: Display live sessions - extra info
```
Visually the UI seem messed as well (it is as the css and js is not loading but I can't pinpoint where the errors are...).

**Pull down this code `$ git pull https://github.com/tochman/WebsiteOne.git event-epic`, fire up  `$ rails s` and see for yourself. If you know what's up, I'd be happy to hear about it.**

hangout['EventInstance link'] could be reverted to hangout['Hangout link']...
OR, better yet, change the features that call this in hangout.feature (there's more than one)..
Given the Hangout for event "Scrum" has been started with details:
      | Hangout link | http://hangout.test | -->
| EventInstance link | http://hangout.test |