appveyor: pack interesting files too, not just lib

Signed-off-by: Ralph Giles <giles@thaumas.net>

appveyor.yml

@@ -17,7 +17,16 @@ build:
   verbosity: minimal
 
 after_build:
-- cmd: 7z a opus.zip win32\VS2015\%PLATFORM%\%CONFIGURATION%\opus.lib include\*.h
+- cmd: >-
+    mkdir %APPVEYOR_BUILD_FOLDER%\artifacts
+
+    cd %APPVEYOR_BUILD_FOLDER%\win32\VS2015\%PLATFORM%\%CONFIGURATION%
+
+    for %%a in (lib dll exp pdb) do if exist opus.%%a copy opus.%%a %APPVEYOR_BUILD_FOLDER%\artifacts\
+
+    cd %APPVEYOR_BUILD_FOLDER%
+
+    7z a opus.zip artifacts\* include\*.h
 
 test_script:
 - cmd: >-