RefExtract: only accpet digits as numeration
RefExtract: only accpet digits as numeration

* Forces digits to be [0-9] instead of all the valid unicode numeration.
  This prevents the value error when trying to convert nummeration to int.

inveniosoftware/invenio,inveniosoftware/invenio,tiborsimko/invenio,tiborsimko/invenio