Changed $excel from protected to public.

[mewben]

This enables chaining methods from PHPExcel itself.

Example:

$obj = Excel::load('temp1.xls'); // Has some contents inside
$obj->excel->getActiveSheet()->setCellValue('F2', 'testing');  // use the excel object to call getActiveSheet
$obj->export('xls'); // export as usual

[MaatwebsiteSupport]

Good idea! Will document it later :)