Add package fio

[w0k3]

Hi Ryan, it's super cool to hear Finnix lives again!

flexible I/O tester is great I/O benchmark tool available in Debian repositories since Jessie. I find it much better alternative to bonnie++. It would be great if you could add other benchmark tools too, for example iozone3.

[rfinnie]

Thanks for the suggestion! I'll add iozone3 immediately. fio looks interesting, but it does pull in 40MB of new dependencies, so I'm hesitant to add it now. I'll make a determination as the next release gets closer.