This vendors the jscience javax.measure package, extracted from
https://repo1.maven.org/maven2/org/jscience/jscience/4.3.1/jscience-4.3.1-sources.jar
Using this package as a dependency leads to conflicting classes, which
we can't solve from gradle. Instead of repackaging the jar file the
easiest solution seems to be to vendor the sources we need.
