A recent trial in Shorewood, Wis., had all the trappings of a minor legal dispute. A disgruntled neighbor. A defendant representing himself who called his own father as a character witness. A $313 fine.  But if academic and devoted dog walker Paul Florsheim gets his way, the case will go all the way up to the Wisconsin Supreme Court and reshape the contours of shoreline access to one of the Great Lakes.  It started when Florsheim started walking his two dogs past the Lake Michigan property of dentist Daniel Domagala, known locally for the time he spends in a Tiki-style…