Multiple build matrix on Appveyor (#63)

appveyor.yml

@@ -1,20 +1,28 @@
 version: 0.2.{build}
 environment:
   TARGET: x86_64-pc-windows-msvc
+  matrix:
+    - PYTHON: "C:/Python27-x64"
+      FEATURES: python2
+    - PYTHON: "C:/Python35-x64"
+      FEATURES: python3
+    - PYTHON: "C:/Python36-x64"
+      FEATURES: python3
+
 install:
+  - "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"
+  - "python --version"
   - ps: Start-FileDownload "https://static.rust-lang.org/dist/rust-nightly-${env:TARGET}.msi"
   - start /wait msiexec /i rust-nightly-%TARGET%.msi INSTALLDIR="%CD%\rust-nightly-%TARGET%" /quiet /qn /norestart
   - call "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\vcvarsall.bat" amd64
   - set PATH=%PATH%;%CD%/rust-nightly-%TARGET%/bin
-  - SET PATH=%PYTHONPATH%;%PATH%
   - rustc -V
   - cargo -V
-  - python --version
+
 build_script:
-  - set PATH=C:\Python27-x64;%PATH%&& cargo build --verbose --features python2
-  - set PATH=C:\Python35-x64;%PATH%&& cargo build --verbose --features python3
-  - set PATH=C:\Python36-x64;%PATH%&& cargo build --verbose --features python3
+  - cargo build --verbose --features %FEATURES%
+
 test_script:
-  - set PATH=C:\Python27-x64;%PATH%&& cargo test --verbose --features python2
-  - set PATH=C:\Python35-x64;%PATH%&& cargo test --verbose --features python3
-  - set PATH=C:\Python36-x64;%PATH%&& cargo test --verbose --features python3
+  - cargo test --verbose --features %FEATURES%
+  - pip install setuptools-rust pytest pytest-benchmark
+  - cd examples/word-count && python setup.py install && pytest -v tests