Merge pull request #5 from lsamayoa/issue-4

Issue 4
Merge pull request #6 from lsamayoa/issue-3

Issue 3
Revert "Issue 3"
Merge pull request #7 from stellar/revert-6-issue-3

Revert "Issue 3"
Revert "Issue 4"
Merge pull request #8 from stellar/revert-5-issue-4

Revert "Issue 4"
Added support for incoming transactions that are not only in stellars. Now transactions are agregated instead of being added directly. Also unsuccessful transactions are not added to the transactions array (engine_result != 0).
Moved dust to stellar conversion to the last step in the balance aggregation to reduce rounding errors.
Removed bug introduced by calculating stellars last.