Updated appveyor config

Author: Dan

appveyor.yml

@@ -98,7 +98,7 @@ install:
   # pip will build them from source using the MSVC compiler matching the
   # target Python version and architecture
   # NOTE: psutil won't install under PyPy.
-  - "pip install -r requirements.txt"
+  - "pip install -r requirements.txt nose"
 
   - ps: "if(Test-Path(\"${env:PYTHON}\\bin\")) {ls ${env:PYTHON}\\bin;}"
   - ps: "if(Test-Path(\"${env:PYTHON}\\Scripts\")) {ls ${env:PYTHON}\\Scripts;}"