Removed pods from .gitignore

This way there's no need to run "pod install" to be able to run the
project
Updated pods

Removed AFOAuth2Client
Removed MBProgressHUD
Added AFNetworking
Added SVProgressHUD
Implemented OAuth with Meetup
Updated pods
Replaced MBProgressHUD with SVProgressHUD
Added APPEvent and defined its interface.
Implemented
Fixed dates issue
Implemented request to get Appsterdam Milan events
Added and Impemented APPVenue
Added venue property
Removed APPMeetupCommunicator as its functionality is in APPMeetupOperationManager
Replaced APPFirstViewController with a Base UIViewController
Added request to get events per type
Added APPTabBarController
Use of APPTabBarController
Fixed repeat issue
Set events view controller title
Implemented loading events using APPMeetupOperationManager
Fixed predicate error