iZettle/izettle-toolbox — pull request #72 by adamvoncorswant (2014-06-15 20:38:22+00:00)
Title: Cart various fixes

When starting to applying the cart library to one or our internal projects (no names mentioned), I discovered a few areas for improvements:

* Using `Float` instead of `Double` when representing `vatPercentage`
* Fixed a bug where discounts with null for either percentage or amount threw a NPE
* Utility method for grouping VAT amounts

Added tests for the fixed bug and the new utility.

Note to reviewer: the above issues were each fixed in separate commits and is probably easiest to look at separately.

ping @xiaodong-izettle or @MrShish