Deleted AppVeyor build definition

.appveyor.yml

@@ -1,33 +0,0 @@
-image: Visual Studio 2017
-
-branches:
-  only:
-  - master
-  - beta
-  - stable
-
-# Don't create a build when a PR is opened
-skip_branch_with_pr: true
-
-nuget:
-  disable_publish_on_pr: true
-  
-skip_commits:
-  files:
-    - 'doc/**/*.*'  
-
-init:
-- ps: git config --global core.autocrlf true
-
-build_script:
-- ps: .\build\build.ps1 -script build\build.cake
-
-artifacts:
-- path: .\build\*.nupkg
-
-deploy:
-  provider: NuGet
-  api_key:
-    secure: aMv5mgCNr/R0IcnSVrwJz7f8C4zSY1lAgJR+B7MLmMJPuPp2FIp426LXc/v66jC1
-  skip_symbols: true
-  artifact: /.*\.nupkg/