Add a storage manager (Files & NSUserDefaults)

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
Rename "by" + add "with" Session attributes

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
[Demo] Better support for anonymous users on demo interface

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
Do not create multiple anonymous users

...if identifyUserWithIdentify:nil is called multiple times

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
Review of error message levels

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
Add CocoaPods badge to README.md

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
Change timeout for POST requests from 5 to 10

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>