Fix for access request on iOS 6

[rainux]

There are 2 issues cause apps use motion-addressbook crash on iOS 6 devices, they got fixed in 2 commits separately.

Now request access manually works properly on iOS 6, however the simplest usage people = AddressBook::Person.all still raise exception if user decide to not allow access, since call to ABAddressBookCopyArrayOfAllPeople on this line https://github.com/alexrothenberg/motion-addressbook/blob/master/motion/address_book/person.rb#L17 will return nil.

Maybe in README we should suggest developers to use manual way only.

[alexrothenberg]

Thanks for this fix.

I wonder what should happen in the people = AddressBook::Person.all case where the user does not grant access. I can imagine it

1. returning nil
2. return an empty list
3. raising an exception

I think 2 sounds best to me. WDYT?

[rainux]

I think 2 sounds best too. To implement it looks like we should change https://github.com/alexrothenberg/motion-addressbook/blob/master/motion/address_book/person.rb#L17 to return [] if call to ABAddressBookCopyArrayOfAllPeople returns nil.

[alexrothenberg]

Do you want to make the fix to https://github.com/alexrothenberg/motion-addressbook/blob/master/motion/address_book/person.rb#L17 ?

[rainux]

OK, I'll send the pull request.

[alexrothenberg]

I merged your pull #13 so AddressBook::Person.all returns [] when not authorized.

Thanks