Fix #81 (https://github.com/larcus94/LBYouTubeView/issues/81) where the regex doesn't correctly find the appropriate URL
The class method `+ (NSURLConnection*)connectionWithRequest:(NSURLRequest *)request delegate:(id)delegate;` "Creates and returns an initialized URL connection and begins to load the data for the URL request.", so calling `[self.connection start];` will fire off an additional request connection resulting in an error.

 `[self.connection start];` should only be used when using the instance method `- (id)initWithRequest:(NSURLRequest *)request delegate:(id)delegate;`
Added additional checks to ensure an error doesn't occur on a second `connectionDidFinishLoading:` call. For some reason `connectionDidFinishLoading:` may get called **despite** actually closing the connection.