add ability to customize ffmpeg path

MediaBrowser.ServerApplication/IO/StartupOptions.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace MediaBrowser.ServerApplication.IO
+{
+    public class StartupOptions
+    {
+        private readonly List<string> _options = Environment.GetCommandLineArgs().ToList();
+
+        public bool ContainsOption(string option)
+        {
+            return _options.Contains(option, StringComparer.OrdinalIgnoreCase);
+        }
+
+        public string GetOption(string name)
+        {
+            var index = _options.IndexOf(name);
+
+            if (index != -1)
+            {
+                return _options.ElementAtOrDefault(index + 1);
+            }
+
+            return null;
+        }
+    }
+}