Two developers decided they have the stomach to turn around one of Oakland's most treasured but wasted buildings: the Henry J. Kaiser Convention. Emeryville-based Orton Development Inc. and Oakland-based Creative Development Partners submitted proposals to the city this month to win the rights to rehabilitate the 215,000 square-foot building that's laid dormant for about a decade. The specific proposals are not yet public, but will head to the City Council in February for final selection, said director…