Download mmm-util-backport-java.util.function JAR file with all dependencies

A backport for java.util.function to be used in java versions older than 1.8. As there are no default methods before 1.8 the backport is very limited. It only allows to create libraries with modern APIs to allow 1.8 code to use nice and natural lambdas without locking out users with older java versions. ATTENTION: This only works with -Xbootclasspath. Also it is inofficial and invalid according to JCP/JSR. However, we need a working update-path to 1.8.