UNITSOFMEASUREMENT-39: Add new content from recent events 

Task-Url: https://java.net/jira/browse/UNITSOFMEASUREMENT-39
UNITSOFMEASUREMENT-27: Epic for design related tasks and issues 
JavaDoc
Task-Url: https://java.net/jira/browse/UNITSOFMEASUREMENT-27
26: Remove redundant types like DoubleMeasurement 

Task-Url:
https://github.com/unitsofmeasurement/unit-impl-se/issues/issues/issue/26
UNITSOFMEASUREMENT-25: Adjust spec document to recent code changes 

Task-Url: https://java.net/jira/browse/UNITSOFMEASUREMENT-25
removing V in Measurement interface