Remove obsolete, unused titan-serve conf file

titan-server-rexster.xml is no longer needed now that
RexsterTitanServer is out
Add XSLT pom stylesheets to support JRE6 builds
Adding pom XSLT stylesheets for JRE retargeting
Flesh out JRE6/7 targeting XSLT sheets

Added retargeting support to the distribution archives, including both
their contents and the filenames of the zip/tar.bz2/asc files.
Removing uses of Java 7's ProcessBuilder.Redirect

This is a convenience introduced in Java SE 7.  I recently used it in
HBase's test harness and in the distribution failsafe tests without
realizing that it wasn't present in Java 6.  This commit replaces it
with a clunkier but functionally equivalent Java 6 alternative.
Fixing titan-dist-all, -server jre6 packaging bug

The jre6.xslt stylesheet now removes the persistit dependencies from
these two distro poms.  I also deleted the jre7.xslt stylesheet, since
reversing this operation is nontrivial.  So now `git checkout` is the
way to reverse it.