Importing `OpenGL.GL` fails on Python 3.5:

```
Python 3.5.1+ (default, Jan 13 2016, 15:09:18) 
[GCC 5.3.1 20160101] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import OpenGL.GL
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3/dist-packages/OpenGL/GL/__init__.py", line 3, in <module>
    from OpenGL.GL.VERSION.GL_1_1 import *
  File "/usr/lib/python3/dist-packages/OpenGL/GL/VERSION/GL_1_1.py", line 10, in <module>
    from OpenGL import platform, constants, constant, arrays
  File "/usr/lib/python3/dist-packages/OpenGL/arrays/__init__.py", line 22, in <module>
    formathandler.FormatHandler.loadAll()
  File "/usr/lib/python3/dist-packages/OpenGL/arrays/formathandler.py", line 28, in loadAll
    cls.loadPlugin( entrypoint )
  File "/usr/lib/python3/dist-packages/OpenGL/arrays/formathandler.py", line 35, in loadPlugin
    plugin_class = entrypoint.load()
  File "/usr/lib/python3/dist-packages/OpenGL/plugins.py", line 14, in load
    return importByName( self.import_path )
  File "/usr/lib/python3/dist-packages/OpenGL/plugins.py", line 28, in importByName
    module = __import__( ".".join(moduleName), {}, {}, moduleName)
  File "/usr/lib/python3/dist-packages/OpenGL/arrays/vbo.py", line 430, in <module>
    def mapVBO( vbo, access=GL.GL_READ_WRITE ):
AttributeError: module 'OpenGL.GL' has no attribute 'GL_READ_WRITE'
```

It seems to work fine in Python 3.4:

```
Python 3.4.4 (default, Jan  5 2016, 15:35:18) 
[GCC 5.3.1 20160101] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import OpenGL.GL
>>> 
```

Or by first importing `OpenGL.GLU`:

```
Python 3.5.1+ (default, Jan 13 2016, 15:09:18) 
[GCC 5.3.1 20160101] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import OpenGL.GLU
>>> import OpenGL.GL
>>> 
```