call pytest with '--pyargs pywt' in appveyor.yml

Author: grlee77

appveyor.yml

@@ -27,7 +27,7 @@ install:
 
 test_script:
   - "util\\appveyor\\build.cmd %PYTHON%\\python.exe setup.py build --build-lib build\\lib\\"
-  - "%PYTHON%\\Scripts\\pytest build\\lib\\pywt\\tests"
+  - "%PYTHON%\\Scripts\\pytest --pyargs pywt build\\lib\\pywt\\tests"
 
 after_test:
   - "util\\appveyor\\build.cmd %PYTHON%\\python.exe setup.py bdist_wheel"