Incorporated Patrick's feedback comment on #211 and made maven build/dep-resolution atleast a bit faster.

Also rename parent project to spark-parent (otherwise it shows up as
"parent" in IntelliJ, which is very confusing).

See the discussion at https://github.com/mesos/spark/pull/355 for why
default profile activation is a problem.

As part of this, changed our Scala 2.9.2 Kafka library to be available
as a local Maven repository, following the example in
(http://blog.dub.podval.org/2010/01/maven-in-project-repository.html)

by using -Dhadoop -Phadoop2.

Fixed repl maven build to produce artifacts with the appropriate hadoop classifier and extracted repl fat-jar and debian packaging into a separate project to make Maven happy

This will make it easier to make the "run" script work with a Maven build