Refactor `create_universe_boundary` to use a collection of boundary edges

[jbtule]

• [x] Instead of each Shape being it's on var such as:

    left  = CP::Shape::Segment.new...
    right  = CP::Shape::Segment.new...
    etc...

put them into a hash ->

   boundaries = {
            left_edge: CP::Shape::Segment.new...
            right_edge: CP::Shape::Segment.new...
            etc...

• [x] use the each_value syntax to set the shapes as sensors on all the boundary shapes at once

   boundaries.each_value {|value| value.sensor = true }

• [x] use the each syntax to set the collision type such as

   boundaries.each {|key, value| value.collision_type = key }

• [x] use the each_value syntax to add each boundary shape to @space
• [x] use the each_key syntax to add the collision handler for each boundary symbol and player