First round of dead file removal

experimental/visual_studio_plugin/src/NaClVsx.Package/Installation/ProgressForm.cs

-using System;
-using System.Collections.Generic;
-using System.ComponentModel;
-using System.Data;
-using System.Drawing;
-using System.Linq;
-using System.Text;
-using System.Windows.Forms;
-
-namespace Google.NaClVsx.Installation
-{
-  public partial class ProgressForm : Form
-  {
-    public ProgressForm()
-    {
-      InitializeComponent();
-    }
-
-    public string Message {
-      get { return message_.Text; }
-      set { message_.Text = value; }
-    }
-
-    public void Cancel() {
-      if (Cancelled != null) {
-        Cancelled(this, null);
-      }
-      this.DialogResult = DialogResult.Cancel;
-      Close();
-    }
-
-    public event EventHandler Cancelled;
-
-    private void cancel__Click(object sender, EventArgs e)
-    {
-      Cancel();
-    }
-
-
-  }
-}