Renamed chxx-* to actual chapter numbers.
Rename ch02 to ch02-mr-intro.
Rename all chapters to be of the form chxx-name.
Convert site files for Important Hadoop Daemon Properties section
to Hadoop 2.
Include vcores setting in yarn-site, and make memory non-default value.
Update snippet configuration to Hadoop 2.
Update to Hadoop 2.5.1.