refs #25 added the download of csar_files
* Added the functionality for downloading csar_files to the ui and the backing bean
* Replaced the treetable with the grouped datatable and removed the TableRow class thatis no longer necessary
* Changed the DownloadCsarService to use UUIDs
* Changed the FileSystem to use UUIDs
* Added the use of UUIDs to the UploadCsarService
refs #25 added column header
added the column headers for fileId and Download
Merge pull request #67 from tothfn/25

Add the download of csar_files, fixes #25 

* Added the functionality for downloading csar_files to the ui and the backing bean
* Replaced the treetable with the grouped datatable and removed the TableRow class thatis no longer necessary
* Changed the DownloadCsarService to use UUIDs
* Changed the FileSystem to use UUIDs
* Added the use of UUIDs to the UploadCsarService