AirMessage for Android 3.1.6

Changes

• The user's proxy type and a conversation's internal ID and service are now reported to Crashlytics
• AirPacker now checks for large allocations before allocating memory
• Dependency updates

Fixes

• Secure shared preferences are now excluded from backups (which could also cause decryption failures)
• Fixed the conversation detail fragment's member detail composite disposables not being cleared when the fragment is destroyed

Code changes

• Converted messaging files to Kotlin