Make sure twitter feeds don't break when OAUTH becomes required

[rjmackay]

https://dev.twitter.com/blog/changes-coming-to-twitter-api

With the recent changes on the twitter api, core will have to change on how we handle pulling and displaying data from twitter. Some of the things that will be required;

• Authentication - Deployers will have to set up their deployments as oauth clients on twitter -> https://twitter.com/oauth_clients/
• This is needed on the twitter serch api which is what we use to pull tweets > https://dev.twitter.com/docs/api/1.1/get/search/tweets
• Tweets Display - Now this calls for changes on how we display tweets. We need to link back to usernames, (valid) hashtags and most of all add some actions (Reply,Retweet,Favourite) - well this creates another level of complexity -> https://dev.twitter.com/terms/display-requirements - The tweets come in as messages on the backend so we can display them there however we want. However, for purposes of displaying them on the frontend, we'll have to adhere to the display guidelines
• Rate limiting - we are talking about 60 calls per hour per-endpoint

How this will work:

1. Anything concerning twitter will all be moved to a tab under the settings tab. Here we link deployers to the twitter oauth client's site.
2. We will store the api-key on the settings table
3. Use the key on the twitter search api + the specified hashtags and pull data.
4. Move the hashtags input field from site settings to the "New Twitter tab settings".
5. On the messages tab, edit the twitter tab - display of information as per the new rules
6. Tweak the twitter scheduler (s_twitter.php) file to handle the new rate limits. This might mean us setting a limit on how fast you can run the twitter schedule.

[brianherbert]

Before oauth hits, we also need to set a limit on how fast you can run the twitter scheduler. They are rate limiting at 60 calls per hour, which means one call per minute.

[rjmackay]

@kamaulynder moving the twitter notes over to this ticket so they're public http://ushpad.com/p/twitter_changes