Merge pull request #119 from soulmachine/master

A little revise for the document

(cherry picked from commit f0e23a023ce1356bc0f04248605c48d4d08c2d05)
Signed-off-by: Reynold Xin <rxin@apache.org>
Merge branch 'branch-0.8' of https://github.com/apache/incubator-spark into master-csd
Moved Debian packaging to assembly sub-project
Moved Debian package build to assembly and refactor to use new shell scripts
Added python directory to Debian package
Merge pull request #1 from markhamstra/assembly-deb

Build enhanced Debian package from assembly