Added optionality of colID in is_method_valid() in order to check ranking method codes regardless of collection.  Fixed documentation of get_bibrank_methods().
Added optionality of colID in is_method_valid() in order to check
ranking method codes regardless of collection.  Fixed documentation of
get_bibrank_methods().

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