Fix in Java 6 compatibility + SesameTripleCallback 

SesameTripleCallback now makes sure startRDF() and endRDF() are called on the internal RDFHandler. Also, JarCacheResource now uses getContentLength instead of getContentLengthLong to make sure code is Java 6-compatible.

Apologies for code formatting gunk (and the version number back-and-forth). Not entirely sure how I can keep that out of the pull request...