[dasher: 32/217] Added note to explain the use of the WIX environmental variable for the build process.

[Patrick Welche <pwelche src gnome org>]

commit 17cde6b2f9371fcd37acaee41ed45d15ea9ed605
Author: Ron Bessems <ron b promixis com>
Date:   Fri Sep 11 19:50:37 2015 -0400

    Added note to explain the use of the WIX environmental variable for the build process.

 INSTALL.Windows |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/INSTALL.Windows b/INSTALL.Windows
index 3f478e8..b00c2a6 100644
--- a/INSTALL.Windows
+++ b/INSTALL.Windows
@@ -73,6 +73,9 @@ XML (WiX) toolset, from http://wix.sourceforge.net/.  For Visual Studio
 version of WiX.  If it installs successfully, you should see "Windows 
 Installer XML Version 3.0" listed in the about box of Visual Studio.
 
+The Visual Studio 2013 project files use the environment variable called 
+"WIX" which should be set to the install directory of WiX.
+
 setup.exe
 ---------