init_options method

Need not called directly if using WorldBuilder

def init_options(args = {})
    args = defaults.merge(args)
    set_options(args[:scale],
                args[:gravity].to_java(Java::float),
                args[:warm],
                args[:continuous]
               )
end

Provides defaults for init_options

def defaults
   { scale: 10.0, gravity: [0, -10], warm: true, continuous: true }
end