More Funbox: hex and guid

[asasine]

Hello, cool website!

It would be fun to have more programmer funboxes.

1. Hexadecimal: 0x[a-f0-9]
2. GUIDs: [:hex:]{8}(-[:hex:]){3}[:hex:]{12}

I can go about adding these if they sound reasonable.

[Miodec]

Sounds good, go for it.