Update TwitterApi.java

- Changed the request and access token endpoints to https.

- Removed the inner SSL class since Twitter now forces to use https instead of http.

- Removed the extend SSL from the Authenticate class since it no longer exists anymore.
Update TwitterApi.java

- Authenticate now extends the TwitterApi class so the @Override annotation is used correctly.
Merge pull request #455 from robindrost/patch-2

Update TwitterApi.java