Replaced a few redundant tests [if Settings.table then ...]
with assertions [assert Settings.table].

Renamed to [listif] and [elementif].

  defined at different places in the generated file (in order to avoid
  name clashes, and for clarity).

The type env no longer needs to be parameterized.
This makes the API safe (and simpler).
There a slight runtime cost (e.g., from 4.6s to 4.7 seconds).

This seems to cause roughly a 10% speed loss (e.g. from 4.3 to 4.6 seconds).
The current interface is not satisfactory, as it allows the user to
manufacture a continuation that will break our invariants and lead
to a crash.

Added links to CompCert's github repository.

Spell-checking.

['a lr1state -> 'a symbol] and maps a state (an abstract datum)
to (a code for) its incoming symbol. This allows inspecting the
semantic values stored in the stack.
Updated the demo [calc-incremental] to display the contents of
the stack at every token. It seems to work!

[lr1state], [element], [stream] and of the function [view].

more general and correct (the old code could change a set of nonrecursive
type definitions into a set of recursive type definitions).

[IL.structure]. This makes the IL more reasonable and flexible. In
principle, the generated code is unchanged.

Fixed the printing of nonrecursive value definitions (use let/and instead
of let/let).

Updated the lexer accordingly.
This has the benefit that a type error in a trailer will be correctly located
in the .mly file. Until now, it wasn't.