add/update comments
delay instantiation of primitives until Namer

get it out of TokenMapper.  this is just a small step towards
eventually delaying instantiation until the middle end.
eliminate command/reporter distinction in TokenMapper, tokens.txt

reifying the distinction everywhere tends to lead of doubling
of code. if we can see what something is just by looking (e.g.
at the Syntax object), then do it that way.
move TokenMapper to compile.front

because it talks about org.nlogo.prim, even if only inside strings
make ExpressionParser less reliant on nvm.Instruction