Merge pull request #101 from RPangrle-MS/OSXUniversal

APEX fixes in OS X Universal
Merge pull request #181 from RPangrle-MS/OSXUniversal

Fixes
Removed OpenSSL dependency files and OpenSSLHelper classes.
Added Keychain support for OSX.
Updated code to remove OpenSSL calls.
Updated sample apps for iOS and OSX.
Fixed keychain issue for OS X and memory leaks

Fixed keychain issue for OS X and memory leaks
Remove exceptions as per issue#63

Remove exceptions as per
https://github.com/AzureAD/azure-activedirectory-library-for-objc/issues
/63.
All the exeptions are returned as Errors to the completion block,
except for the case when completion block itself is null.
Addressed warning messages

Addressed warning messages
Over releasing of object

Over releasing of object
Fix for#182

Fix for #182
Fixed casing error in then header file

Fixed casing error in then header file
Addressed issue#180

Addressed issue#180
Addressed code review comments

Addressed code review comments
Addressed code review comments

Addressed code review comments
Merge pull request #190 from AzureAD/OSXUniversal-dev

Osx universal dev
Add a setting that allows consumers to pass in a block to add custom access policies to keychain entries.