Added -all method to NSArray and NSSet

[subramanianv]

Added the method (BOOL) -all:(block)

This is my first commit to an open source project. Let me know if I have to fix anything

[supermarin]

duplicate #68

[subramanianv]

I am newbie here. Is this a duplicate pull request ?

[supermarin]

@subramanianv it's implemented in #68, but not merged in yet.
I'm not sure if it'll make it in master tho.

[jonahb]

@supermarin, what do you mean "it's implemented in #68"? #68 is an issue, not a pull. I'd like this feature too.

[shepting]

The [NSArray all:] and [NSArray any:] methods are two that I really miss from Python. I'd vote for this to go in.

http://docs.python.org/2.7/library/functions.html#all

[shepting]

Maybe use the enumerateObjectsWithOptions:usingBlock method though to allow concurrent checking of all the items in the block.

[jonahb]

That would be slower than a loop in most cases.

[supermarin]

I'm sorry for the misunderstanding, was probably tired and closed the wrong PR / issue.
Closing #68, reopening this one