functionaljava/functionaljava — pull request #26 by ms-tg (2012-12-19 19:44:01+00:00)
Title: Improve HashMap with #map, #mapValues, #mapKeys, #foreach

Improve `HashMap` by implementing the following methods that we have found useful:
* `#map`
* `#mapKeys`
* `#mapValues`
* `#foreach`

In addition, add conversion to/from `java.util.Map`, and filter out calls to `#set` with a `null` value.