Blender Git Loki

dissallow access to the context while addons import and register.
Since the window manager is needed for keymaps this is kept as an exception.

some addons will need updating, but in every case I've seen addons should not be accessing the context while registering.
(bad stuff! - declaring the scene as a global variable - which crashes when the users loads a new file, manipulating the active object or scene... tsk tsk)