HADOOP-2205. Regenerate the Hadoop website since some of the changes made by HADOOP-1917 weren't correctly copied over to the trunk/docs directory. Also fixed a couple of minor typos and broken links. Contributed by Arun C. Murthy.
HADOOP-1917. Addition of guides/tutorial for better overall documentation for Hadoop. Specifically: * quickstart.html is targetted towards first-time users and helps them setup a single-node cluster and play with Hadoop. * cluster_setup.html helps admins to configure and setup non-trivial hadoop clusters. * mapred_tutorial.html is a comprehensive Map-Reduce tutorial.