CI: Temporarily drop all other tests

Author: effigies

appveyor.yml

@@ -5,19 +5,9 @@ environment:
   DEPENDS: numpy scipy matplotlib h5py pydicom
 
   matrix:
-    - PYTHON: C:\Python27
-    - PYTHON: C:\Python27-x64
-    - PYTHON: C:\Python34
-    - PYTHON: C:\Python34-x64
-    - PYTHON: C:\Python35
-    - PYTHON: C:\Python35-x64
     - PYTHON: C:\Python35-x64
       PYTHONHASHSEED: 283137131
       DEPENDS: "h5py==2.9.0"
-    - PYTHON: C:\Python36
-    - PYTHON: C:\Python36-x64
-    - PYTHON: C:\Python37
-    - PYTHON: C:\Python37-x64
 
 install:
   # Prepend newly installed Python to the PATH of this build (this cannot be