Updates README for setup_script

Updates README to reflect setup_script build capabilities and requirements to setup binaries and includes for sample applications. Fixes #24

platforms/winrt/readme.txt

@@ -17,14 +17,29 @@ Install Visual Studio Express 2012 for Windows Desktop
 
 
 
-To create all Windows Phone (8.0, 8.1) and Windows Store (8.0, 8.1) Visual Studio projects
+To create and build all Windows Phone (8.0, 8.1) and Windows Store (8.0, 8.1) Visual Studio projects
 ==========================================================================================
 cd opencv/platforms/winrt
-setup_winrt.bat "WP,WS" "8.0,8.1" "x86,ARM"
+setup_winrt.bat "WP,WS" "8.0,8.1" "x86,ARM" -b
 
 If everything's fine, a few minutes later you will get the following output in the opencv/bin directory:
 
 bin
+    install
+        WP
+            8.0
+                ARM
+                x86
+            8.1
+                ARM
+                x86
+        WS
+            8.0
+                ARM
+                x86
+            8.1
+                ARM
+                x86    
     WP
         8.0
             ARM
@@ -40,7 +55,11 @@ bin
             ARM
             x86
 
-Build the OpenCV.sln for the particular platform you are targeting. Due to the current limitations of CMake, separate x86/x64/ARM projects must be generated for each platform.
+'-b' flag in the command above builds each generated solutions in both 'Debug' and 'Release' configurations. It also builds the predefined 'INSTALL' project within generated solutions. Building it creates a separate install location that accumulates binaries and includes for specified platforms. Default location is ```<ocv-src>\bin\install\```.
+
+WinRT samples reference 'install' binaries and include files via ```OPENCV_WINRT_INSTALL_DIR``` environment variable. Please declare it and point to ```<ocv-src>\bin\install\``` directory (note slash at the end) to resolve references within sample applications.
+
+If you don't want to build all configurations automatically, you can omit ```-b``` flag and build OpenCV.sln for the particular platform you are targeting manually. Due to the current limitations of CMake, separate x86/x64/ARM projects must be generated for each platform.
 
 You can also target a single specific configuration
     setup_winrt.bat "WP" "8.1" "x86"
@@ -99,4 +118,4 @@ To generate Windows Phone 8.1 x86 project files in the opencv/bin dir
 
 mkdir bin
 cd bin
-cmake -G "Visual Studio 12 2013" -DCMAKE_SYSTEM_NAME=WindowsPhone -DCMAKE_SYSTEM_VERSION=8.1 ../
\ No newline at end of file
+cmake -G "Visual Studio 12 2013" -DCMAKE_SYSTEM_NAME=WindowsPhone -DCMAKE_SYSTEM_VERSION=8.1 ../