Allows to download private blogs

- Allows to download private blogs (#4).
- Adds a new downloader that uses a different method to crawl the tumblr
network that allows to bypass the safe mode and download private
content, but requires a login. Thus, it's only used for private blogs
even though crawling normal, non-private blogs would be possible too.
This downloader could grab more meta information and does not require
the tumblr api.

src/TumblThree/TumblThree.Applications/Controllers/ManagerController.cs

@@ -356,6 +356,13 @@ private async Task AddBlogAsync(string blogUrl)
             TransferGlobalSettingsToBlog(blog);
             IDownloader downloader = DownloaderFactory.GetDownloader(blog.BlogType, shellService, crawlerService, blog);
             await downloader.IsBlogOnlineAsync();
+
+            if (CheckIfTumblrPrivateBlog(blog))
+            {
+                blog = PromoteTumblrBlogToPrivateBlog(blogUrl);
+                downloader = DownloaderFactory.GetDownloader(blog.BlogType, shellService, crawlerService, blog);
+            }
+
             await downloader.UpdateMetaInformationAsync();
 
             lock (lockObject)
@@ -373,6 +380,25 @@ private async Task AddBlogAsync(string blogUrl)
             }
         }
 
+        private bool CheckIfTumblrPrivateBlog(IBlog blog)
+        {
+            if (blog.BlogType == BlogTypes.tumblr && !blog.Online)
+            {
+                return true;
+            }
+            return false;
+        }
+
+        private IBlog PromoteTumblrBlogToPrivateBlog(string blogUrl)
+        {
+            IBlog blog;
+            blog = new Blog(blogUrl, Path.Combine(shellService.Settings.DownloadLocation, "Index"), BlogTypes.tmblrpriv);
+            TransferGlobalSettingsToBlog(blog);
+            blog.BlogType = BlogTypes.tmblrpriv;
+            blog.Online = true;
+            return blog;
+        }
+
         private void TransferGlobalSettingsToBlog(IBlog blog)
         {
             blog.DownloadAudio = shellService.Settings.DownloadAudios;