Remove breaks after returns
Reorder AIResponseData.h
Restructure AIRequestHandler
Refactor request response handling
Reorder AIActivityHandler methods
Add optional parameter transactionId to trackRevenue methods
Update revenue tests
Inject transactionId into revenueInternal
Add array of transaction IDs to activityState
Add method [AIActivityState addTransactionId:]
Add method [AIActivityState findTransactionId]
Add [AIActivityHandler checkTransactionId:] to skip duplicate IDs
Update Readme
Rename doc/{migration → migrate}.md
Mention transactionId parameter in migration quide
Remove trailing whitespace
Update version to 3.1.0
Merge pull request #37 from adjust/transaction-ids

Add optional parameter transactionId to trackRevenue methods