Merge pull request #29 from otaviojava/adjust_api

ajudst to new api
UNITSOFMEASUREMENT-53: Measurement extends Comparable 

Task-Url: https://java.net/jira/browse/UNITSOFMEASUREMENT-53
UNITSOFMEASUREMENT-53: Measurement extends Comparable 

Task-Url: https://java.net/jira/browse/UNITSOFMEASUREMENT-53
adjust to new API and refacotr the QuantityFactory
fix test