Adding initial crypto helpers, tests
Interim checkin.  Adding SFPBKDFData objects
Adding NSCoding implementation to PBKDF data object
Passcode provider implementation
Changing protocol method name
Implement PBKDF2 passcode provider
Adding passcode provider tests
Starting SFPasscodeManager tests
More passcode tests
Updating SmartStore tests to test both passcode providers.
Adding new SalesforceCommonUtils headers to projects
Merge pull request #223 from khawkins/encryption_updates

Refactor to passcode provider, add PBKDF2 provider