(Portland, OR)  --  Police say they've arrested a man accused of waving a knife and hatchet at passing motorists on Northwest Everett Street.  Officers arrested 30-year-old Joseph L. Dedman at about 7 a.m. yesterday, a short distance away from the scene on Northwest Couch Street.  They found a knife and hatchet nearby.  Dedman faces disorderly conduct and weapons charges, as well as a possible mental-health assessment.