Add ability to send data by userId

Add ability to send data by userId

1.2016.09.15 Release

Adds in support for messageIds with push notifications.

1.2016.08.16 Release

Adds in functionality to play custom sounds for push notifications.

1.2016.07.04 Release

Removed registerForPush/disablePush with signature (string, boolean)
Changed function permissions in IterableApi

1.2016.06.30 Release

Adds in option to toggle logging for debugMode via sharedInstanceWithApiKey

1.2016.07.05 Release

Fixes retry logic.
Adds in error checking for null Context in GCM registration.

Release 1.0.2016.06.29

Updates play-services gcm version to match available FCM version. Resolves conflict when adding in FCM library to the project.

Release 1.0.2016.06.28

Fixed up code review changes in iterableRequest
Adds checks to not process push notifications for the app not from Iterable
Moves setting the payload earlier before calling trackOpen.
Updated stored Context to be the applicationContext. Changed sharedInstanceWithApiKey to take in a more strict activity
Updates Context for sharedPrefs to not required to be an Activity.

Stable Release

Stable release on jCenter with base SDK functionality.
BinTray public repo: https://bintray.com/davidtruong/maven/Iterable-SDK/view
Integration documentation here: http://support.iterable.com/hc/en-us/articles/204780589