Remove C++03 compilers from appveyor.yml

appveyor.yml

@@ -15,10 +15,7 @@ branches:
 environment:
   matrix:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0
-      ADDRMD: 32
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      TOOLSET: msvc-12.0,msvc-14.0
+      TOOLSET: msvc-14.0
       ADDRMD: 32,64
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       TOOLSET: msvc-14.1
@@ -44,7 +41,6 @@ install:
 build: off
 
 test_script:
-  - PATH=%ADDPATH%%PATH%
   - if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
   - if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
   - b2 -j3 libs/lambda/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker