Testing all variants in appveyor

Author: zajo

appveyor.yml

@@ -40,4 +40,7 @@ build: off
 
 test_script:
   - if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
-  - b2 -j3 libs/leaf/test toolset=%TOOLSET% %CXXSTD%
+  - b2 -j3 libs/leaf/test toolset=%TOOLSET% variant=debug %CXXSTD%
+  - b2 -j3 libs/leaf/test toolset=%TOOLSET% variant=release %CXXSTD%
+  - b2 -j3 libs/leaf/test toolset=%TOOLSET% variant=debug-discard-unexpected %CXXSTD%
+  - b2 -j3 libs/leaf/test toolset=%TOOLSET% variant=release-discard-unexpected %CXXSTD%