add MovieLens tutorial
modify data path
Merge branch 'movielens' into ampcamp4
update nav weight for mllib
update ALS code for ec2
add matrix factorization image
add the bigger data set
hide some solutions in the tutorial
use spark-mllib-0.9.0 release
delete sbt-launch jar
updated env setup for ampcamp cluster
tuned training parameters
minor updates to md
Merge pull request #127 from jegonzal/graphx-tutorial

Additional cleanups to GraphX tutorial
Merge pull request #125 from mengxr/ampcamp4

Add personalized movie recommendations to ampcamp4
fixing bugs
more edits to later parts of second section