title: R TwitteR and Rate-Limit Issues
body: <p>I have experienced what appears to be vastly inconsistent behaviour with TwitteR package in R. I fire queries as follows, each in its 15-min window for compliance with rate-limiting feature of REST API 1.1. The first three work. The 4th fails. Repeatedly.</p>
  
  <pre><code>monsanto.tweets = searchTwitter('@monsanto', n = 1500);  
  monsanto.tweets.20131207 = searchTwitter('@monsanto', n = 6000, until = '2013-12-07'); 
  monsanto.tweets.20131205 = searchTwitter('@monsanto', n = 6000, until = '2013-12-05');
  monsanto.tweets.20131202 = searchTwitter('@monsanto', n = 6000, until = '2013-12-02');
  </code></pre>
  
  <p>Error is:
      [1] "Client Error (429)"
      Error in twInterfaceObj$doAPICall(cmd, params, "GET", ...) : 
          Error: Client Error (429)</p>
  
  <p>How is that? I have tried experimenting with the count, stepping it down to 1000 in steps of 1000. No success. I have also tried variations upon the theme.</p>
  
  <pre><code>monsanto.tweets.20131202 = searchTwitter('@monsanto', 
      since = '2013-12-02', until = '2013-12-02', lang = 'en');
  monsanto.tweets.20131130 = searchTwitter('@monsanto', 
      n = 1000, until = '2013-11-30');
  </code></pre>
  
  <p>None of these work. Under the hood, each instance of 'searchTwitter' likely generates multiple GET requests to the REST API 1.1. Per documentation, a single GET request returns upto 100 tweets, defaulting to 25. Fulfilling a request for 6000 tweets should require 60 requests at best and 240 requests at the default setting. Both are within the permissible limit of 480/application in a 15 min window.</p>
  
  <p>What gives?</p>
  
  <p>PS - I use OAuth. I am beginning to think I am better off hand-rolling my own interface to the REST API 1.1 and parsing JSON. </p>