Askari::Packaging.append_java_classpath! sets up the java classpath.

Further, `require 'askari'` invokes it, meaning that require is enough
to put the gem in a usable state.

Note that coprocessor jars still need to use the pathmap since the
bootstrap code must be in the root of the coprocessor jar.
Merge pull request #55 from seomoz/phs/setup-classpath-on-load

Askari::Packaging.append_java_classpath! sets up the java classpath.