Split definitions in mark-sweep intro into a nw chapter and add terminology notes
Add glossary entry for internal pointer
Remove parenthetical phrase from pointer defn
Add note about quantifiers to preliminary definitions
Clarify context of live cell invariant (it's a thing which we need to show to hold)
Add \pointsto to preliminary definitions
Preliminary Definitions -> The Language of Garbage Collection, and give first paragraph the prelim defns heading
Move statement of Armstrong/Virding into a figure
Add little notational aside footnote explaining the use of typewriter font
Separate statement of lemma and proof in mark-sweep partial correctness
Make proof headings bold, not italic
Be more consistent about type()/pointer/data/gc formatting (all mathrm)
Remove trivial from copying
Remove trivial from marksweep
Don't refer to definition numbers in ms summary, and split forward/backward bits