Add MultiPart/MimePart Request Matcher (#981)

* wip

* .

* mm

* x

* .

* .

* .

* tests

* .

* more tests

* trans

* x

* win

* fix

* .

* tests

tools/MultipartUploader/Form1.cs

@@ -0,0 +1,10 @@
+namespace MultipartUploader
+{
+    public partial class Form1 : Form
+    {
+        public Form1()
+        {
+            InitializeComponent();
+        }
+    }
+}