Added PHPExcel as a dependency for Composer
Class to handle XLSX (Office Open XML Excel 2007 and above) format.
This is a barebone class at this point, not doing anything fancy yet...
Almost there
Finished XLSX export
Added dumb XLS export as a simple modification of XLSX one.
Clean up needed!
Added buttons to download both XLS and XLSX files.
Need to update the names later...
Minor change in download buttons text
Separation of classes for better objects relation and code reuse.
Added a configuration entry to list download formats for the users
Merge branch 'downloaddropdown' into excelwriter

Conflicts:
	templates/default/html/report.twig
Added Excel formats to the download dropdown
Merge pull request #65 from uded/excelwriter

Created an Excel writer - capable of preparing both Excel 97-2003 and Excel 2007+ files