Merge pull request #216 from AzureAD/OSXUniversal

Osx universal
Merge pull request #218 from AzureAD/OSXUniversal

Osx universal
Issue #215

Fix for
https://github.com/AzureAD/azure-activedirectory-library-for-objc/issues
/215. Updated the code to use global queue as a default and use main
queue only for UI operations.
fixed variable name

fixed variable name
missed change

missed change
Ryan's fix to remove static signal

Ryan's fix to remove static signal
Merge pull request #228 from AzureAD/OSXUniversal-dev

Osx universal dev