Appveyor: remove mingw

.appveyor.yml

@@ -4,31 +4,15 @@ clone_folder: C:\GOPATH\src\github.com\osteele\liquid
 
 environment:
   GOPATH: C:\GOPATH
-
-cache:
-  - C:\mingw64 -> appveyor.yml
+  GOVERSION: 1.8
 
 init:
-  - set PATH=C:\mingw64\bin;C:\go\bin;%GOPATH%;%PATH%
+  - set PATH=C:\go\bin;%GOPATH%;%PATH%
   - go version
   - go env
-  - set CC=gcc
-  - set CXX=g++
 
 install:
-  - ps: |
-      # Install MinGW.
-      $url = "https://bintray.com/artifact/download/drewwells/generic/x86_64-5.1.0-release-win32-seh-rt_v4-rev0.7z"
-      $strFileName="C:\mingw64\bin\mingw32-make.exe"
-      If (Test-Path $strFileName){
-        Write-Host "Using cached mingw64"
-      }Else{
-        Write-Host "Fetching mingw64"
-        Invoke-WebRequest -UserAgent wget -Uri $url -OutFile ming32-64.7z
-        &7z x -oC:\ ming32-64.7z > $null
-      }
   - go get -t ./...
-  - pip install Pygments
 
 build_script:
   - go test ./...