- exported API methods left at the same place
- private methods moved to helpers.go
- stuff for testing moved to testutils.go
- created storage interface with clean API and multi transaction related db calls moved
to MultiTransactionDBStorage implementation
- created dummy in-mem storage for tests with multi transactions
- written tests for MultiTransactionDBStorage
- Get rid of InsertTestMultiTransaction function in test utils and
use InsertMultiTransaction method of transaction manager
- Use MultiTransaction type instead of TestMultiTransaction
Added a missing wallet DB migration file for multi transactions
`getLogs` for multiple accounts simultaneously. For now only used for
new transfers detection. Detection of `new` transfers has been changed,
now they are searched from head and forward. Previously they were
searched from last scanned block forward.