Polish create-msvs-files script

create-msvs-files.bat

@@ -1,14 +1,21 @@
-@REM Hello World
+@echo off
 
 cd %~dp0
 
-IF EXIST %~dp0build\gyp GOTO WINDIR
-
+if exist build\gyp goto have_gyp
 
+echo svn co http://gyp.googlecode.com/svn/trunk@983 build/gyp
 svn co http://gyp.googlecode.com/svn/trunk@983 build/gyp
+if errorlevel 1 goto gyp_install_failed
+goto have_gyp
 
-:WINDIR
-
-@python gyp_uv
+:gyp_install_failed
+echo Failed to download gyp. Make sure you have subversion installed, or 
+echo manually install gyp into %~dp0build\gyp.
+goto exit
 
+:have_gyp
+python gyp_uv
+if not errorlevel 1 echo Done.
 
+:exit