Log Message:
Update ruby-twitter to 5.14.0.

5.14.0
------
* [Add \ 
`Twitter::NullObject#respond_to?`](https://github.com/sferik/twitter/commit/438e311d93f382960650e20898203c880ade6b25)
* [Add `Twitter::Media::Video`, `Twitter::Media::VideoInfo`, and \ 
`Twitter::Media::Variant`](https://github.com/sferik/twitter/commit/158193f85843ebac7b3188bbad26d73907577f6a)
* [Add `Twitter::Media::AnimatedGif` media \ 
entity](https://github.com/sferik/twitter/commit/76cb6645a54969edc7c9195e9e27e3728f5fd683) \ 
([@nidev](https://twitter.com/nidev))

5.13.0
------
* [Deprecate `Twitter::REST::Client#get` and \ 
`Twitter::REST::Client#post`](https://github.com/sferik/twitter/commit/65773c7d741098490f4164fae9e4433365cd4292)
* [Rename `Twitter::REST::Client::URL_PREFIX` to \ 
`Twitter::REST::Client::BASE_URL`](https://github.com/sferik/twitter/commit/73e2b9be19acf1403f324e5be48a550d3756d822)
* [Extract `Twitter::Headers` \ 
class](https://github.com/sferik/twitter/commit/e0d4c36bade95253b98b3ee657af409bfeadbbb6)
* [Move `Twitter::Request` to \ 
`Twitter::REST::Request`](https://github.com/sferik/twitter/commit/a46d9f21067724c437d40c7cb9c609f6cd304df1)
* [Add \ 
`Twitter::REST::Request#rate_limit`](https://github.com/sferik/twitter/commit/0c9f9d6a15835a0260a5a56a8aaffdc3f3e39eed)
* [Rename `Twitter::REST::Utils` \ 
methods](https://github.com/sferik/twitter/commit/2b1cceca0d37a038d3afd0b5763f2308b3db1b2d)
* [Update default `User-Agent` to comply with Section 5.5.3 of RFC \ 
7231](https://github.com/sferik/twitter/commit/e5eb8d451d8be2d2751e6dda132c65039e5c879c)

5.12.0
------
* [Rescue `Twitter::Error::NotFound` for safe `#favorite` and \ 
`#retweet`](https://github.com/sferik/twitter/commit/5e6223df20217fd6b0ac78b44b0defdb46d1e018)
* [Make `Twitter::User#profile_background_image_uri` methods return a \ 
URI](https://github.com/sferik/twitter/commit/d96194c0c3b17076e48faed1b05cd48d043a6778)
* [Un-deprecate \ 
`Twitter::Base#to_hash`](https://github.com/sferik/twitter/commit/f45ce597408ab2bae2b55db6456543bf6d9ea081)
* [Add \ 
`Twitter::Tweet#possibly_sensitive?`](https://github.com/sferik/twitter/commit/917e8f14f7707eb646e8057827ed0ba9d1766eeb)
* [Namespace registered Faraday \ 
middleware](https://github.com/sferik/twitter/commit/a96931171e32c142f36318547f2cffa6ccd5c199) \ 
([@godfoca](https://twitter.com/godfoca))
* [Fix test failures on Ruby \ 
2.2.0-preview1](https://github.com/sferik/twitter/commit/74fb2e676f5882c62a6d4f07d7bbf8ca1f469fe2)
* [Make Twitter::NullObject \ 
Comparable](https://github.com/sferik/twitter/commit/9635db5128708525f3368800f11c519d6b14b1e4)

5.11.0
------
* [Return a Twitter::NullObject for empty \ 
attributes](https://github.com/sferik/twitter/commit/bca179eefb1c157f19b882a88ba608f6817b76bb)
* [Add `iso_language_code` attribute to \ 
`Twitter::Metadata`](https://github.com/sferik/twitter/commit/7bf3a1b6ad0c35dc608b03ba2b3321b594e4da1c)

5.10.0
------
* [Add support for extended \ 
entities](https://github.com/sferik/twitter/commit/ed7c708e4208de1df27d141678c14e23422504a0)
* [Add \ 
`Twitter::REST::Client#upload`](https://github.com/sferik/twitter/commit/f5a747b53c4866bb378d6022f309d6176620122e)