add automatic game installer and updater

- download and install LCEWindows64.zip automatically
- update Minecraft.Client.exe from nightly releases
- detect installed version using commit hash
- add progress window for downloads
- store version in releaseinfo.txt

Form2.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Windows.Forms;
+
+namespace LegacyConsoleLauncher
+{
+    public partial class Form2 : Form
+    {
+        public Form2()
+        {
+            InitializeComponent();
+        }
+
+        public void SetStatus(string text)
+        {
+            label1.Text = text;
+            label1.Refresh();
+        }
+
+        public void SetProgress(int value)
+        {
+            if (value < 0) value = 0;
+            if (value > 100) value = 100;
+
+            progressBar1.Value = value;
+            progressBar1.Refresh();
+        }
+    }
+}