Key Configuration

Key Configuration

Keymaps are now saveable and configurable from the user preferences, note
that editing one item in a keymap means the whole keymap is now defined by
the user and will not be updated by Blender, an option for syncing might be
added later. The outliner interface is still there, but I will probably
remove it.

There's actually 3 levels now:

* Default builtin key configuration.
* Key configuration loaded from .py file, for configs like Blender 2.4x
  or other 3D applications.
* Keymaps edited by the user and saved in .B.blend. These can be saved
  to .py files as well to make creating distributable configurations
  easier.

Also, user preferences sections were reorganized a bit, now there is:
Interface, Editing, Input, Files and System.

Implementation notes:
* wmKeyConfig was added which represents a key configuration containing
  keymaps.
* wmKeymapItem was renamed to wmKeyMapItem for consistency with wmKeyMap.
* Modal maps are not wrapped yet.
* User preferences DNA file reading did not support newdataadr() yet,
  added this now for reading keymaps.
* Key configuration related settings are now RNA wrapped.
* is_property_set and is_property_hidden python methods were added.