POM cleanup and enhancement to ease hadoop download.

  - Sets source encoding to UTF-8
  - Updates typo in README for path checked withing user's home directory for local Hadoop
  - Updates hadoop 0.20.2 download to archive.apache
  - Adds a profile to handle the download and extraction of hadoop before tests
  - Auto activates said profile when easy flags of a Hadoop install aren't present
  - Updates README to reflect changes to profile

This update allows for a clean run of ```mvn install``` on a clean system that doesn't have Hadoop. You can walk through the testing for Hadoop by setting appropriate system conditions and using ```mvn help:active-profiles```.

  - On new checkout on clean system, should show "download-hadoop" as active
  - If ${HADOOP_HOME} is set, should show "hadoop-home-defined" and not "download-hadoop"
  - If ${HOME}/hadoop/hadoop-0.20.2_local is present, should show "hadoop-installed-in-home-dir" and not "download-hadoop"
  - If we've run through a download before, should show "hadoop-in-target" and not "download-hadoop"
  - If we've run through a download before and then done a ```mvn clean```, should show "download-hadoop" again.