error arc + warning __block redefined

just fix little mistakes.

`retain ~> ah_retain` to fix error
and you redefined `__block` and xCode fires a warning
so, I called it `ah__block`

Actually, I don't think you need to redefined it..
because there are no called to `__block` in your library.

The user who used `UzysSlideMenu` is the person
who can use `__block`  in his code.
Thus, if he know what he does,
he has to use `__block` or `__weak` and it doesn't affect your library.