v0.9 update

Changes for v0.9. Mostly an expansion of optional rules, and rearranging around optional rules.

• Added option for critical rolls. (under GM "Rolls" section)
• Added lots more optional rules, expanding that section from 2 pages to 4 pages.
• Reformatted References & Inspiration section.

Changes for v0.7. Lots of minor updates, nothing substantial. 

• Adjusted entries on the character tables
• Tiny increase in font size. Probably unnoticeable? The serif font looking smaller than the sans serif font in the character tables just bugged me.
• Added max ability/HP for created NPCs.
• Clarified when to apply flexible magic's drawbacks -- basically everything except minor/cosmetic magic.
• Adjusted various word/expression choices. Some for succinctness, some for clarity.
• Adjusted Companion rules to be clear it takes the player's action to ask them to do things (so someone with a hundred companions doesn't slow the game down for other players). 
• Added Trade rules, just to hint (but not limit) that bartering is preferred to tracking coin.