Tests. Enable Python 2.6, 3.5 on AppVeyor

appveyor.yml

@@ -5,6 +5,15 @@ environment:
     # See: http://stackoverflow.com/a/13751649/163740
     WITH_COMPILER: "cmd /E:ON /V:ON /C .\\scripts\\run_with_compiler.cmd"
   matrix:
+    # https://www.appveyor.com/docs/installed-software/#python
+    - PYTHON: "C:\\Python26"
+      PYTHON_VERSION: "2.6.6"
+      PYTHON_ARCH: "32"
+
+    - PYTHON: "C:\\Python26-x64"
+      PYTHON_VERSION: "2.6.6"
+      PYTHON_ARCH: "64"
+
     - PYTHON: "C:\\Python27"
       PYTHON_VERSION: "2.7.9"
       PYTHON_ARCH: "32"
@@ -28,6 +37,14 @@ environment:
     - PYTHON: "C:\\Python34-x64"
       PYTHON_VERSION: "3.4.3"
       PYTHON_ARCH: "64"
+
+    - PYTHON: "C:\\Python35"
+      PYTHON_VERSION: "3.5.2"
+      PYTHON_ARCH: "32"
+
+    - PYTHON: "C:\\Python35-x64"
+      PYTHON_VERSION: "3.5.2"
+      PYTHON_ARCH: "64"
 init:
   - ps: |
       $ErrorActionPreference = "Stop"