use static imports
revert
218258196404718887c250efb77099d115b1f3fe
96ef08480de4726dda544e8fa6a32a36863e0dfd
e6ae545c34af8aecb22f22bf35d5f17c6c7f5ed4
http://forum.routeconverter.com/thread-1503.html
add tests for unit systems