Removed System.Windows.Forms dependancy from Common. Almost done removing NLog dependancy.

MediaBrowser.Logging.NLog/NlogManager.cs

@@ -0,0 +1,50 @@
+using NLog;
+using NLog.Config;
+using NLog.Targets;
+
+namespace MediaBrowser.Logging.Nlog
+{
+    /// <summary>
+    /// Class NlogManager
+    /// </summary>
+    public static class NlogManager
+    {
+        /// <summary>
+        /// Adds the file target.
+        /// </summary>
+        /// <param name="path">The path.</param>
+        /// <param name="enableDebugLogging">if set to <c>true</c> [enable debug logging].</param>
+        public static void AddFileTarget(string path, bool enableDebugLogging)
+        {
+            var logFile = new FileTarget();
+
+            logFile.FileName = path;
+            logFile.Layout = "${longdate}, ${level}, ${logger}, ${message}";
+
+            AddLogTarget(logFile, "ApplicationLogFile", enableDebugLogging);
+        }
+
+        /// <summary>
+        /// Adds the log target.
+        /// </summary>
+        /// <param name="target">The target.</param>
+        /// <param name="name">The name.</param>
+        /// <param name="enableDebugLogging">if set to <c>true</c> [enable debug logging].</param>
+        private static void AddLogTarget(Target target, string name, bool enableDebugLogging)
+        {
+            var config = LogManager.Configuration;
+
+            config.RemoveTarget(name);
+
+            target.Name = name;
+            config.AddTarget(name, target);
+
+            var level = enableDebugLogging ? LogLevel.Debug : LogLevel.Info;
+
+            var rule = new LoggingRule("*", level, target);
+            config.LoggingRules.Add(rule);
+
+            LogManager.Configuration = config;
+        }
+    }
+}