Remove accidentally committed appveyor file.

appveyor.yml

-environment:
-  matrix:
-  - configuration: Release
-branches:
-  only:
-    - master
-
-clone_folder: c:\libzmq
-
-build_script:
-  - md c:\build
-  - cd c:\build
-  - echo Running cmake...
-  - cmake -G "Visual Studio 12" -DCMAKE_BUILD_TYPE=%Configuration% c:\libzmq
-  - cmake --build .
-  
-test_script:
-  - cd c:\build
-  - ctest -C %Configuration%