Urban Airship integration support + bug fixes

• Added support for Urban Airship integration. Learn more here: https://mixpanel.com/platform
• Remove the possibility of dereferencing a null pointer #738
• Updated podspec with necessary frameworks #743
• Removed some globals that were colliding with other variable names #755

App extension back to Mixpanel.podspec + misc fixes

• No longer have two separate podspecs for iOS apps and app extensions #715
• Fix mini in app positioning on iphone X #731
• Fix a UIControl not on main thread bug (thanks @michalcichon) #733
• Make it so alias implicitly calls identify as that's almost required and which identifier to call identify with after alias is confusing #730

Bug fix

• Fixing an issue where the packaged framework included LLVM code coverage due to how we were building with Carthage. #727

Bug fix

• Fixed a crash from UNUserNotifications push notifications #723

Minor changes + bug fixes

• Allow people distinct id to not be set to guarantee people profiles won't be created in Mixpanel. #708
• Allow automatic Mixpanel push notification tracking to track UNUserNotificationCenter as well. #713
• Add properties for cta url and primary/secondary button for in app notification tracking. #714
• Fix UIApplication access from background thread. #714
• Fix signal handling so it properly passes it on to crash reporters. Add an option on initializing Mixpanel to not initialize signal and exception handling. #718

Mixpanel push tracking improvements + bug fixes + Xcode 9 beta

• Automatically track push notification opened for Mixpanel notifications #697
• Bug fix for A/B test people profile tracking before users were identified #693
• Bug fix for SKIP_INSTALL (thanks @filblue)! #699
• Fix module maps for public and private headers #698
• Bug fix for modifying a running A/B test #705
• FIxes for new warnings in Xcode 9 #703
• Bug fix for flushing on backgrounding #706

Bug fixes

• Add more safety around not showing duplicate in-app notifications #689
• Fix a crash in automatic properties if there was an error getting the device model #690
• Better namespacing in signal and exception handling #692

Minor changes and bug fixes

• Add support for tracking notification journeys #682
• Fixed a bug that caused identical events to be dropped #681
• Fixed Xcode 9 beta warnings

Minor changes

• Added eventElapsedTime: to allow you to check the ongoing time for a timed event. This can be used however you want, e.g. only tracking if a minimum time has gone by. #642
• Stopped calling UIApplication setNetworkActivityIndicatorVisible: from a background thread. #677
• Ensured logging would only occur from one thread at a time. #664

Added automatic tracking of common mobile events

With this release we are adding automatic tracking of common mobile events. These events include tracking app sessions, first app opens, in-app purchases, app updated, and app crashed.
The feature will be rolled out slowly to all our users, and can be turned on in Project settings under Autotrack.
To configure the tracking of app sessions, we now expose two new properties, minimumSessionDuration and maximumSessionDuration. These properties provide lower and upper bounds on the session lengths that your app will track.