Fix building the binary on appveyor, and have it create an artifact.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

appveyor.yml

@@ -1,9 +1,10 @@
 
+version: '{branch}-{build}'
+
 install:
   - "SET PATH=C:\\Python27-x64;C:\\Python27-x64\\Scripts;%PATH%"
   - "python --version"
-  - "pip install tox==2.1.1"
-
+  - "pip install tox==2.1.1 virtualenv==13.1.2"
 
 # Build the binary after tests
 build: false
@@ -13,3 +14,7 @@ test_script:
 
 after_test:
   - ps: ".\\script\\build-windows.ps1"
+
+artifacts:
+  - path: .\dist\docker-compose-Windows-x86_64.exe
+    name: "Compose Windows binary"