Tweaks for SeLion Grid:
* Extraction:
  * Added dependency for the commons-compress library for extracting artifacts
  * Leveraged the ArchiveStreamFactory to deal with .zip,.tar and .tar.bz2
  * Made extraction specific to platforms

* Download:
  * Tweak downloads as per the platform
  * Refactored GridAutoUpgradeServlet to display fields as per the platform

* Fixed IndexOutOfBoundException in AbstractProcessHandler
* Removed the .json template files that had the names of artifacts and its relevant
  extracted binary name. This adds overhead in maintaining the artifact names in two places.
* Added unit tests
* Addressed review comments
* Changed the URL and checksum for Linux artifacts to x86 platform
* Changed the executable name for IEDriverServer to lowercase to maintain uniformity in comparison
* Separating the FileExtractor to a separate class to handle extraction
Minor code tweaks

* Added the license header for some classes.
* Ripped out EmailAssistant class which is NOT being
used.
* Reduced visibility of FileExtractor to a package
visible class and added a private constructor