added the ability to control the accessibility level for each value. see this for more details on why it is important: https://blog.loom.com/how-we-fixed-the-ios7-forced-logout-bug-thats-been-plaguing-so-many-apps/
enabled PDKeychainBindings to support accessibility per value.
added a missing method...
Merge pull request #10 from yosit/master

added the ability to control the accessibility level for each value.
Merge branch 'master' of https://github.com/carlbrown/PDKeychainBindingsController into barz-master

Conflicts:
	PDKeychainBindingsController/PDKeychainBindingsController.h
	PDKeychainBindingsController/PDKeychainBindingsController.m