Update hitbox drawing functions to allow both RGB and RGBA colors

[pushfoo]

Enhancement request:

What should be added/changed?

Allow the following to take RGB instead of just RGBA:

1. SpriteList.draw_hitb_boxes
2. BasicSprite.draw_hit_box

What would it help with?

This is a follow-up to #1838 and other RGB / RGBA issues since some users prefer using only RGB.