jwatjars : Java '.jar' Files for 'jwatr'

By separating out 'JAR' files from 'rJava'-based packages, such packages can have a lighter filesystem footprint, especially when they are likely to change at a more rapid pace than the underlying libraries they depend upon. Core library files from the 'Java Web Archive Toolkit' https://sbforge.org/display/JWAT/JWAT.

Intended to be used with jwatr.