Drop support for python2.7

python2.7 requires building with visual studio 2008 which doesn't
support c++ 11.

appveyor.yml

@@ -15,14 +15,6 @@ environment:
     WHEELHOUSE_UPLOADER_USERNAME: travis-worker
 
   matrix:
-    - PYTHON: C:\Python27
-      PYTHON_VERSION: 2.7
-      PYTHON_ARCH: 32
-
-    - PYTHON: C:\Python27-x64
-      PYTHON_VERSION: 2.7
-      PYTHON_ARCH: 64
-
     - PYTHON: C:\Python34
       PYTHON_VERSION: 3.4
       PYTHON_ARCH: 32
@@ -90,12 +82,6 @@ install:
     - del /Q zlib-src.zip
 
 before_build:
-    - if %PYTHON%==C:\Python27 set generator=Visual Studio 9 2008
-    - if %PYTHON%==C:\Python27 set vcplatform=Win32
-
-    - if %PYTHON%==C:\Python27-x64 set generator=Visual Studio 9 2008 Win64
-    - if %PYTHON%==C:\Python27-x64 set vcplatform=x64
-
     - if %PYTHON%==C:\Python34 set generator=Visual Studio 10 2010
     - if %PYTHON%==C:\Python34 set vcplatform=Win32