Aded Data Helper and Session Helper

These are two objects I find myself using a lot. I feel like the Class Name "Data" might be a bit too generic and would advise an alternate name, nothing came to mind right away.
this is unnecessary because [we already require PHP 5.4](https://github.com/kohana/ohanzee-helpers/blob/0b7cf7038abb09a0ff48101c1e151e37c252297a/composer.json#L30).