New AggregationRule s

With the version 7.1 release, this crate introduces two new (AggregationRule)s.
First the TickRule triggers the candle creation every n tick (trades).
The second new AlignedTimeRule is similar to the TimeRule but additionally makes sure the candles are aligned to the start of the period.

A thank you goes out to @dam5h for creating the AlignedTimeRule.

Happy algotrading everyone!