change references from winnt to windows

rename sys/winnt to sys/windows
move vs (visual studio) folder out of win/win32 and into sys/windows
rename include/ntconf.h to include/windconf.h
rename winnt.c to windsys.c
place visual studio projects into individual subfolders.

This will hopefully resolve GitHub issue #484 as well.

sys/windows/win10.h

@@ -0,0 +1,46 @@
+/* NetHack 3.7	win10.h	$NHDT-Date: 1596498319 2020/08/03 23:45:19 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.8 $ */
+/* Copyright (C) 2018 by Bart House 	 */
+/* NetHack may be freely redistributed.  See license for details. */
+
+#ifndef WIN10_H
+#define WIN10_H
+
+#include "win32api.h"
+
+#ifdef __MINGW32__
+#ifndef DECLARE_HANDLE
+#define DECLARE_HANDLE(name) struct name##__{int unused;}; typedef struct name##__ *name
+#endif
+DECLARE_HANDLE(DPI_AWARENESS_CONTEXT);
+
+/* DPI awareness */
+typedef enum DPI_AWARENESS
+{
+    DPI_AWARENESS_INVALID = -1,
+    DPI_AWARENESS_UNAWARE = 0,
+    DPI_AWARENESS_SYSTEM_AWARE,
+    DPI_AWARENESS_PER_MONITOR_AWARE
+} DPI_AWARENESS;
+
+#define DPI_AWARENESS_CONTEXT_UNAWARE              ((DPI_AWARENESS_CONTEXT)-1)
+#define DPI_AWARENESS_CONTEXT_SYSTEM_AWARE         ((DPI_AWARENESS_CONTEXT)-2)
+#define DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE    ((DPI_AWARENESS_CONTEXT)-3)
+#define DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2 ((DPI_AWARENESS_CONTEXT)-4)
+#define DPI_AWARENESS_CONTEXT_UNAWARE_GDISCALED    ((DPI_AWARENESS_CONTEXT)-5)
+#endif
+
+typedef struct {
+    double  scale;  // dpi of monitor / 96
+    int     width;  // in pixels
+    int     height; // in pixels
+    int     top; // in desktop coordinate pixel space
+    int     left; // in desktop coordinate pixel space
+} MonitorInfo;
+
+void win10_init();
+int win10_monitor_dpi(HWND hWnd);
+double win10_monitor_scale(HWND hWnd);
+void win10_monitor_info(HWND hWnd, MonitorInfo * monitorInfo);
+BOOL win10_is_desktop_bridge_application(void);
+
+#endif // WIN10_H