Move Windows and FreeBSD CI to Travis

Remove the AppVeyor and Cirrus config files.

Author: ararslan

.cirrus.yml

@@ -2,16 +2,18 @@ language: julia
 os:
   - linux
   - osx
+  - freebsd
+  - windows
 julia:
-  - 1.3
+  - 1
   - nightly
 notifications:
   email: false
 coveralls: true
 jobs:
   include:
     - stage: "Documentation"
-      julia: 1.3
+      julia: 1
       os: linux
       script:
         - julia --project=docs/ -e 'using Pkg;