Add comments and format the code

Add comments to package tachyon.worker and format the code.
Merge pull request #263 from PasaLab/comment-worker

Add comments to package tachyon.worker
minor tweak tachyon.worker package
better loging to jenkins
Fix extra space from hadoop- env.sh to hadoop-env.sh in mapreduce doc.
Merge pull request #264 from hsaputra/fix_extra_space_in_hdfs_doc

Fix extra space from hadoop- env.sh to hadoop-env.sh in mapreduce doc.
on mac if java home is set use it
logging for jenkins
Merge branch 'master' of github.com:amplab/tachyon
add more logging to LocalTachyonClusterMultiMaster
glusterfs also respects java home for mac
Update README.md
Merge pull request #266 from dcapwell/feature/javahome

on mac if java home is set use it