Added upload to file manager.

FilenamePromptForm.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace MeshCentralRouter
+{
+    public partial class FilenamePromptForm : Form
+    {
+        public string filename
+        {
+            get { return mainTextBox.Text; }
+            set { mainTextBox.Text = value; }
+        }
+
+        public FilenamePromptForm(string operation, string filename)
+        {
+            InitializeComponent();
+            mainGroupBox.Text = operation;
+            mainTextBox.Text = filename;
+            okButton.Enabled = (filename.Length > 0);
+        }
+
+        private void mainTextBox_TextChanged(object sender, EventArgs e)
+        {
+            okButton.Enabled = (mainTextBox.Text.Length > 0);
+        }
+
+        private void okButton_Click(object sender, EventArgs e)
+        {
+            DialogResult = DialogResult.OK;
+        }
+
+        private void cancelButton_Click(object sender, EventArgs e)
+        {
+            DialogResult = DialogResult.Cancel;
+        }
+    }
+}