Edited Issue: ArgumentNullException on SearchTweets [2280]

Hello there,

I keep getting ArgumentNullExceptions when I try to search for Tweets. Stack Trace:
```
bei System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
bei Tweetinvi.Search.SearchTweets(ITweetSearchParameters tweetSearchParameters)
bei TwitterAppV0.Classes.TwitterAPI.SearchQuery() in c:\*somewhere*\Classes\TwitterAPI.cs:Zeile 115.
```
The exception is: Value must not be NULL. Parametername: source
Code:
```
_search_query = Search.GenerateSearchTweetParameter(_query_string);
_search_query.Since = _starting_date;
_search_query.SinceId = _since_tweet_id;
_search_query.MaxId = _until_tweet_id;
_search_query.MaxId = _search_results[_index].Id - 1;
_search_query.MaximumNumberOfResults = 100;
_search_query.SearchType = SearchResultType.Recent;
_search_results = Search.SearchTweets(_search_query); /* crashes here */
```
I'm using the newest version of the library (0.9.3.3). With the older version of the library (0.9.2.3) I constantly got NullReferenceExceptions.

Kind regards,
Wolfram
Comments: ** Comment from web user: linvi **

There is a bug in Tweetinvi.Search when receiving a WebException. I will update the code tonight and release 0.9.3.4 that will only fix this issue tonight too.

Thank you for reporting the issue.
Linvi