`Packaging.classpath` is either the classes dir or the wrapping jar.

It is meant to be a real filesystem path in all situations.
Particularly, if askari is packaged within an application jar, it
should be a path to the jar itself.  This allows it to be used when
starting the hadoop or hbase CLI programs as a classpath entry in all
scenarios.
Merge pull request #102 from seomoz/phs/packaging-offers-classpath-entry-even-within-wrapping-jar

`Packaging.classpath` is either the classes dir or the wrapping jar.