Use stageId as index for fileSet caches.
Subclass URLClassLoader instead of using reflection
Formatting
Merge branch 'dev' into feature/fileserver

Conflicts:
	core/src/main/scala/spark/SparkContext.scala
Merge pull request #195 from dennybritz/feature/fileserver

Spark HTTP FileServer
Adding docs directory containing documentation currently on the wiki
which can be compiled via jekyll, using the command `jekyll`. To compile
and run a local webserver to serve the doc as a website, run
`jekyll --server`.
Updated base README to point to documentation site instead of wiki, updated
docs/README.md to describe use of Jekyll, and renmaed things to make them
more consistent with the lower-case-with-hyphens convention.
Merge pull request #197 from andyk/doc

Adds a "docs" directory containing existing Spark documentation and doc build instructions
Wait for Akka to really shut down in SparkEnv.stop()
Fix bugs with Connection's shutdown callback failing to get its address
Ported performance and FT improvements from latest streaming work
Store shuffle map outputs as DISK_ONLY
Fixing lots of broken links.
Removed the upper-case version of docs/EC2-Scripts.md.
Fixing a hanging sentence in docs/ec2-scripts.md
Merge remote-tracking branch 'public-spark/dev' into doc
Changed block storage level for shuffle to DISK_ONLY.
Added a link to AMPCamp website in Spark docs.
Adds syntax highlighting (via pygments), and some style tweaks to make things
easier to read.
Merge remote-tracking branch 'public-spark/dev' into doc