Feedback fixes!

This update adds some changes based on great feedback from the Stellagama Discord server and a Good Reader from my Wednesday night group. 

• VERY specific rules for Dogs in Space, splits Cats in Space into Space Lions and Space Cats, and adds a bit of a variant for first aid for Electric Sheeple.
• The tables are a little bit rearranged, but not 100% fixed. Some of the problematic, misplaced or over-sized tables may need to move into the inside cover layout. (Should I add a Space Hog species???)
• Major update to the introduction's Concept/Aim/Tone/Subject text on the first page.

Most of the effort (for this update) has gone into better explaining the core concept of the game -- you play heroes in your favorite space opera setting, whether that's public domain, something you wrote yourself, or adapting something else. By its nature, this game WANTS you to take the controls and fit these rules to the game you want to play.