Bump development version to 0.8.0
SPARK-724 - Have Akka logging enabled by default for standalone daemons

See the JIRA for more details.

I was only able to test the bash version (don't have Windows)
so maybe check over that the syntax is correct there.
Updating based on code review
Merge remote-tracking branch 'jey/bump-development-version-to-0.8.0'

Conflicts:
	docs/_config.yml
	project/SparkBuild.scala
Merge pull request #553 from pwendell/akka-standalone

SPARK-724 - Have Akka logging enabled by default for standalone daemons
Merge branch 'master' of https://github.com/mesos/spark into UnusedImports