Fix exception with `me.debug.renderCollisionMap` enabled
Merge branch 'master' into ticket-103
Fix another case of global variable use
Fixed link to the documentation
Do not call `obj.destroy()` early in `me.game.remove()` (the removal may be deferred)

- Fixes some questionable uses of `me.game.remove()` inside callbacks.
- Calling `me.game.remove()` from a callback with `force == true` or `me.game.removeAll()` will NEVER be safe. Update docs to include this warning.
Updated location of the tutorial
adding @agmcleod changes + 'screencanvas' extension support

@see https://github.com/melonjs/melonJS/pull/190
Make `force` optional when calling `me.game.removeAll()`. This makes the function pseudo-safe to use from callbacks.
Merge branch 'master' into ticket-103
[#103] Change collision result into an object
ticket #193 : removed the tutorial from the melonjs main branch now that it has a new home

@see https://github.com/melonjs/tutorial
few changes here and there on the 'screencanvas' extension support

I finally change the `vendorExt` to a private parameter (not publicized)
Add collision_test to illustrate performance improvements in ticket #103
[#103] Super-optimize the collision spacial grid.
Merge branch 'master' into ticket-103