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.rc

@@ -0,0 +1,23 @@
+#include <windows.h>
+#include "xW-resources.h"
+
+// Beware of this madness https://gitlab.kitware.com/cmake/cmake/-/issues/23066
+CREATEPROCESS_MANIFEST_RESOURCE_ID RT_MANIFEST "xW.manifest"
+
+IDI_ICON ICON "xW.ico"
+IDI_HIGHLIGHTED ICON "xW-highlighted.ico"
+
+IDA_ACCELERATORS ACCELERATORS
+BEGIN
+	"^p",     ID_PREVIOUS_BUFFER
+	"^n",     ID_NEXT_BUFFER
+	VK_F5,    ID_PREVIOUS_BUFFER,             VIRTKEY
+	VK_F6,    ID_NEXT_BUFFER,                 VIRTKEY
+	VK_PRIOR, ID_PREVIOUS_BUFFER,    CONTROL, VIRTKEY
+	VK_NEXT,  ID_NEXT_BUFFER,        CONTROL, VIRTKEY
+	VK_TAB,   ID_SWITCH_BUFFER,      CONTROL, VIRTKEY
+	"!",      ID_GOTO_HIGHLIGHT,     ALT
+	"a",      ID_GOTO_ACTIVITY,      ALT
+	"H",      ID_TOGGLE_UNIMPORTANT, ALT
+	"h",      ID_DISPLAY_FULL_LOG,   ALT
+END