accespt uppercase ASC and DESC as sort orders

at least one user has gotten confused by doing a serach like this...

http://localhost:8983/solr/shop/select/?indent=on&facet=true&sort=prijs%20ASC&start=0&rows=18&fl=id,prijs,prijseenhe
id,artikelgroep&q=:&facet.field=artikelgroep&facet.mincount=1

and getting this error...

Can't determine Sort Order: 'prijs ASC', pos=5

... i can't think of any reason why it would be bad to accept both uppercase and lowercase versions of "asc" and "desc"

http://mail-archives.apache.org/mod_mbox/lucene-solr-user/201302.mbox/%3C0A03B892A1F8E14C8D9E8DCB8320052804F30FDC@EX2010-MAIL1.WIZARD.PVT%3E