- maybe store more counters in thm-restate? currently, you cannot re-use
  equation numbers, for example. Those all need to be carried around via
  \label or equivalent.

- when using framed, restated version has different vertical spacing. 
  Oh dear oh dear, might be some addvspace artifact?

- ref close-by/far-away
- complex refs
  (these two are very similar)

- re pre/posthooks: nesting nightmare: addposthook should _pre_pend and 
  addprehook should _ap_pend. Still, check what we know about the order in which
  kv executes the options. FIXED by implementing and using \g@prependto@macro
  kv stuff might not matter: a key such as "shaded" that wants to add an 
  environment should immediately do both, and user should specify keys in
  right order (i.e. "prehook, posthook, shaded" or "shaded, prehook, posthook"
  but *not* "prehook, shaded, posthook").
  
  
- starred theorems and number in list-of-theorems
  FIXED by empty \thefoo macro for starred theorems.
- getting envname via currenvir is unsafe for theorems (think restatable)
  FIXED by manually changing \@currenvir in restatable.
  FIXED by new hooks that def\thmt@thmname et al. in the theorem itself.