SPARK-1184: Update the distribution tar.gz to include spark-assembly jar

See JIRA for details.

Author: Mark Grover <mark@apache.org>

Closes #78 from markgrover/SPARK-1184 and squashes the following commits:

12b78e6 [Mark Grover] SPARK-1184: Update the distribution tar.gz to include spark-assembly jar
(cherry picked from commit cda381f88cc03340fdf7b2d681699babbae2a56e)

Conflicts:

	assembly/pom.xml