added advice about restarting zk and mysql if not already running
minor edits for clarity
fixed broken url to hadoop setup instructions
fixed broken url to other tutorial
Merge branch 'master' into igalDruid
more paper updates
Merge branch 'master' of github.com:metamx/druid
Merge pull request #402 from metamx/igalDruid

Igal druid
edits to paper
Merge branch 'master' of github.com:metamx/druid