[VS Addin] Add visual studio 2012 support

visual_studio/NativeClientVSAddIn/test_2012.bat

Index: visual_studio/NativeClientVSAddIn/test_2012.bat
diff --git a/visual_studio/NativeClientVSAddIn/test.bat b/visual_studio/NativeClientVSAddIn/test_2012.bat
old mode 100755
new mode 100644
similarity index 74%
copy from visual_studio/NativeClientVSAddIn/test.bat
copy to visual_studio/NativeClientVSAddIn/test_2012.bat
index a6475b23fc5bf7e07714b63483414a81d78f4cb9..5a9ac231345aaa52eae976a0a653a12b351fc636
--- a/visual_studio/NativeClientVSAddIn/test.bat
+++ b/visual_studio/NativeClientVSAddIn/test_2012.bat
@@ -1,12 +1,13 @@
 @echo off
+setlocal
 
 :: Locations
 set out_directory=..\..\out\vs_addin\Test
 set mstest_file=Results.trx
-set test_assembly=..\..\out\vs_addin\Debug\UnitTests.dll
+set test_assembly=..\..\out\vs_addin\2012\Debug\UnitTests.dll
 
 :: Set up the Visual Studio environment
-call "%VS100COMNTOOLS%vsvars32.bat"
+call "%VS110COMNTOOLS%vsvars32.bat"
 
 :: Make the output directory and clean up existing mstest result file
 mkdir %out_directory%
@@ -17,4 +18,8 @@ mstest /testcontainer:%test_assembly% /testsettings:Local.testsettings /resultsf
 
 :: Parse the result with python script, return python's exit status
 python check_test_results.py %out_directory%\%mstest_file%
-exit /B %ERRORLEVEL%
+
+endlocal & set BUILD_ERRORLEVEL=%ERRORLEVEL%
+
+:endbuild
+exit /B %BUILD_ERRORLEVEL%