V2.x.x regex extend plus tonumber

Greetings,

it's my first contribution to FreeRADIUS (and also first time doing any collaboration via GitHub). I will write a relevant mail to the list, but we need the functionality to match more regex groups in unlang than the standard 8 (%{0}..%{8}), plus translate strings to numbers (eliminating initial zeroes for example).
It is a patch for the 2.X.X (stable blanch) and I would love to see the functionality included upstream and not maintain it locally.

Regards and thanks for the useful software,

Kostas Zorbadelos