Windows: Update INSTALL_WIN.txt

Add info regarding where the 'INSTALL' file comes from.

Remove link for Windows SDKs as this is no longer relevant.

Update to account for Visual Studio 2019.

Closes #235

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>
diff --git a/INSTALL_WIN.txt b/INSTALL_WIN.txt
index 783a479..3ee364d 100644
--- a/INSTALL_WIN.txt
+++ b/INSTALL_WIN.txt
@@ -1,13 +1,15 @@
 Installation Instructions for Windows
 *************************************
 
-If you are compiling for MinGW or cygwin, please refer to the INSTALL file.
+If you are compiling for MinGW or cygwin, please refer to the INSTALL file,
+which is automatically generated by autotools (e.g. running bootstrap.sh).
 
 If you are using Microsoft Visual Studio:
 - Open the relevant solution file in /msvc:
   libusb_2013.sln for Visual Studio 2013,
   libusb_2015.sln for Visual Studio 2015,
-  libusb_2017.sln for Visual Studio 2017 or later.
+  libusb_2017.sln for Visual Studio 2017,
+  libusb_2019.sln for Visual Studio 2019 or later.
 - If you want to debug the library, uncomment the ENABLE_DEBUG_LOGGING define
   in msvc\config.h
 - Select your configuration and compile the project
@@ -47,6 +49,3 @@
 
 Additional information related to the Windows backend:
   http://windows.libusb.info
-
-Microsoft Windows SDK Archive:
-  https://developer.microsoft.com/en-us/windows/downloads/sdk-archive
\ No newline at end of file
diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 3951592..8a29e15 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11539
+#define LIBUSB_NANO 11540