Api changes and other compatibility notes

cocos 0.6.6
-----------

	- this is exactly 0.6.5 except that pip or setup.py install will select pyglet < 1.4
	- this version is not compatible with pyglet 1.4

cocos 0.6.5
-----------

	- First cocos version to support pyglet 1.3 , tested against pyglet 1.3.rc1
	- This cocos version can also run with pyglet 1.2.x
	- Next cocos version will drop support for python 2.6
	- Python 2.7 support can end at any future cocos release, without further advice: if pyglet drops it or a cocos new feature requires more than trivial compatibility code, then cocos will be py3 only

cocos 0.6.4
-----------

Imports in cocos library are more specific, so user code that were doing
``from cocos.somemodule import *`` may fail to find some symbols.
To fix that user code, add explicit exports as needed.

MapColliders classes changed API to be more useful and clear. 
    - :class:`~.mapcolliders.RectMapCollider` moved to his own module, 
      :mod:`.mapcolliders`.
    - :class:`~.mapcolliders.RectMapCollider` was renamed to 
      :class:`.RectMapWithPropsCollider`.
    - The new :class:`~.mapcolliders.RectMapCollider` handles a simpler 
      collision case, when all tiles are solid: now no need to set cells 
      properties to signal a cell border should not be walked over.
    - :class:`.TmxObjectMapCollider` now handles AABB collision with any 
      :class:`.TmxObject` that can be loaded.

:meth:`.Rect.intersects()` now it only intersects if some interior points
overlaps.

Removed :class:`.Scene` methods ``push_all_handlers()`` and 
``remove_all_handlers()``.

In :class:`.ScrollingManager` two methods have been renamed, the old name is
still valid but will be removed in the future:

  - ``pixel_from_screen()`` \-> ``screen_to_world()``
  - ``pixel_to_screen()`` \-> ``world_to_screen()``

