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.
you have to be careful with ctype_digit, it will trigger an error if `$data` is not a string. this code should read:

```lang=php
if (is_int($data) || (is_string($data) && ctype_digit($data))) { ... }
```

also the empty check will invalid results that are `0` or `'0'`, both of which are valid digits for the purpose of this test.