Improved the support for dragging and dropping images from a website, now also parsing HTML img src information, to be able to download that image. For this we need the HtmlAgilityPack.dll (#294)

Removed a lot of dead code, and remove the old OCR code as we don't even know if it still works.

GreenshotPlugin/UnmanagedHelpers/Enums/ThreadAccess.cs

@@ -1,17 +1,30 @@
-using System;
+/*
+ * Greenshot - a free and open source screenshot tool
+ * Copyright (C) 2007-2021 Thomas Braun, Jens Klingen, Robin Krom
+ * 
+ * For more information see: http://getgreenshot.org/
+ * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 1 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System;
 
 namespace GreenshotPlugin.UnmanagedHelpers.Enums
 {
     [Flags]
     public enum ThreadAccess : int {
-        TERMINATE = (0x0001),
         SUSPEND_RESUME = (0x0002),
-        GET_CONTEXT = (0x0008),
-        SET_CONTEXT = (0x0010),
-        SET_INFORMATION = (0x0020),
-        QUERY_INFORMATION = (0x0040),
-        SET_THREAD_TOKEN = (0x0080),
-        IMPERSONATE = (0x0100),
-        DIRECT_IMPERSONATION = (0x0200)
     }
 }