donwload and install in yml

.appveyor.miktex.ps

@@ -1,2 +0,0 @@
-wget http://ctan.math.washington.edu/tex-archive/systems/win32/miktex/setup/basic-miktex-2.9.5721-x64.exe -OutFile ./basic-miktex.exe
-basic-miktex.exe --unattended --portable --user-config=%LOCALAPPDATA%\MiKTeX\2.9 --user-data=%LOCALAPPDATA%\MiKTeX\2.9 --user-install=%LOCALAPPDATA%\MiKTeX\2.9

.appveyor.yml

@@ -23,7 +23,8 @@ install:
   - "python -c \"import struct; print(struct.calcsize('P') * 8)\""
 
   # Install miktex
-  - "powershell C:/projects/patacrep/.appveyor.miktex.ps"
+  - ps: "wget http://ctan.math.washington.edu/tex-archive/systems/win32/miktex/setup/basic-miktex-2.9.5721-x64.exe -OutFile ./basic-miktex.exe"
+  - cmd: basic-miktex.exe --unattended --portable --user-config=%LOCALAPPDATA%\MiKTeX\2.9 --user-data=%LOCALAPPDATA%\MiKTeX\2.9 --user-install=%LOCALAPPDATA%\MiKTeX\2.9
 
   - cmd: dir %LOCALAPPDATA%
   - cmd: dir %LOCALAPPDATA%\MiKTeX
@@ -45,4 +46,4 @@ test_script:
 
 # Cache Miktex install
 cache:
-- C:\Users\appveyor\AppData\Local\MiKTeX\2.9 -> .appveyor.miktex.ps
+- C:\Users\appveyor\AppData\Local\MiKTeX\2.9 -> .appveyor.yml