Add :place_id attribute to Spot.

Posted on Google Places API as of June 24, 2014:

Note: The id and reference fields are deprecated as of June 24, 2014. They are replaced by the new place ID, a unique identifier that can be used to compare places and to retrieve information about a place. The Places API currently returns a place_id in all responses, and accepts a place_id in the Place Details and Place Delete requests. Soon after June 24, 2015, the API will stop returning the id and reference fields in responses. Some time later, the API will no longer accept the reference in requests. We recommend that you update your code to use the new place_id instead of id and reference as soon as possible.
Update gems, remove deprecated calls in tests, and remove bad tests.

- Update VCR and remove deprecated methods in favor of new ones (see: https://gist.github.com/kincorvia/4540489).
- Configure VCR to hook_into :webmock since :fakeweb has been deprecated.
- RSpec :should was deprecated, change to :expect
- Remove tests expecting RequestDeniedError raised when the :sensor parameter is not supplied as this is no longer the case.

Also, some general cleanup:
- double quotes to single quotes
Merge branch 'tonyghita-update_tests'
Fixed broken tests
Merge branch 'place_id' of https://github.com/tonyghita/google_places into tonyghita-place_id
Merge branch 'tonyghita-place_id'
Locked dependency versions, pushed version 0.22.0 of the gem
Search single Spots with place_id instead of reference

See: https://developers.google.com/places/documentation/search
for deprecation of id and reference keys
Add viewport attr_accessor on Spot
Add new VCR cassette
Merge branch 'jimmykarily-change_reference_to_place_id'
Bump gem version
Merge pull request #60 from jimmykarily/add_viewport_in_spot

Add viewport attr_accessor on Spot
Bump gem version
Update Gemfile.lock
Add support for auto-complete API

* Add prediction support
* Add language support
Fix failing specs

* Update to use expect syntax
* Use vcr options
Update README with Google Prediction details
Use new google place_id
Update README with limits