Add a Win32 frontend for xC

This has been more of an exercise.  The performance of Msftedit.dll
is rather abysmal, and its interface isn't the most accomodating.

That said, the frontend is quite usable, at least on Windows 10+.

xW/xW.svg

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg version="1.1" width="48" height="48" viewBox="0 0 48 48"
+   xmlns="http://www.w3.org/2000/svg">
+
+  <defs>
+    <clipPath id="outer">
+      <rect x="-1" y="-0.15" width="5" height="3.30" />
+    </clipPath>
+    <clipPath id="inner">
+      <rect x="-1" y="0" width="5" height="3" />
+    </clipPath>
+  </defs>
+
+  <g transform="translate(6, 6) scale(12)" stroke-linecap="square">
+    <g clip-path="url(#outer)">
+      <path stroke="#ffffff" stroke-width="1.5" d="M 0.5,0 2.5,3" />
+      <path stroke="#ffffff" stroke-width="1.5" d="M 0.5,3 2.5,0" />
+    </g>
+    <g clip-path="url(#inner)">
+      <path stroke="#000000" stroke-width="0.2" d="M 0,0 2,3 M 1,0 3,3" />
+      <path stroke="#ff6600" stroke-width="0.3" d="M 0,3 2,0 M 1,3 3,0" />
+    </g>
+  </g>
+</svg>