Fixed object initial visible flag value not being set
fixed both `pauseOnBlur` and `StopOnBlur` both being enabled by default

I let `pauseOnBlur` to true so that we restore the same behavior than
in previous version.
[#284] attempt at fixing event unsubscribe when the layer is destroyed
prep'ing for a maintenance release
typo fix
fixed documentation for `me.save.add`
Fixed group opacity setting overwriting child objects default opacity setting

Also factorized relative code by moving all the alpha and corresponding
getter/setter in the renderable class
Enabled alpha blending between group and relative child objects
Make ScreenObject use screen corrdinates and zero position vector to fix inViewport hit testing
fixed an undefined tileset issue when adding a new Tile through the `seTile` function
Its used as a hash should be initialized. Chrome console was very confused ;)
Merge pull request #292 from agmcleod/anim-array-to-hash

Anim array to hash
Fix `me.Renderable.inViewport` with nested `me.ObjectContainer`s
Better fix for me.Renderable.inViewport with nested ObjectContainers

- Does not modify the object or viewport, so the translation is not visible to the object while updating.
- Uses a temporary me.Rect as a translation context (acts as a stack)
- Translation context is used for the viewport hit detection, instead of the object.
Small optimizations
Update changelog
Fixing horrific bugs!
Cache object position for undoing global translation context; objects will change their position during update.
added a new function to automatically set a property to a given value for all existing childs
cached a reference to `me.game.viewport` for faster access within the update/draw loop