All variables local to a block are now introduced in domain states as soon as
the analysis enters the block. This ensures all variables in scope have always
been introduced in domain states, even when a goto statement jumps to a block
after the declaration of some local variables, skipping their initializations
(these variables would have been introduced in the states, but not initialized).

As a downside, variables explicitly initialized at declaration enter the scope
too early, as they should be introduced on the fly when encountering their
[Local_init] instruction.

Better callstacks in Eva

See merge request frama-c/frama-c!4207

Replaces [set_call_stack] by [init_call_stack].
Removes [legacy_call_stack], which is never used.

Comments all function in the interface.

- The callstack type is not private anymore. Only the current callstack in
  Eva_utils should not be modified without using push/pop; everywhere else,
  functions can freely create callstacks if needed.
  Removes function [change_thread], as it is now useless.

- [pop] only returns the new callstack: this simplifies all its current uses.

- new function [last_caller] returning the function from the penultimate call.

- new function [pretty_debug] to allow using Hptmap on callstacks.

In Eva_utils, the reference to the current callstack is None until the
analysis of the main function starts.

[register_initial_state] now takes the kernel_function as argument.
This avoids using [Callstacks.top_kf] in the store.

[e-acsl] typing, translation: add some debug messages

See merge request frama-c/frama-c!4233

[e-acsl] define Analyses_datatype.Profile.pretty

See merge request frama-c/frama-c!4235

[Dev] update reference configuration

See merge request frama-c/frama-c!4236

Hitherto this function was defined as Datatype.undefined leading to
an exception in Translate_terms.to_exp with -e-acsl-verbose 4 because of
the call to Profile.pretty that takes place.

Fix/alias/issue1278

Closes #1278

See merge request frama-c/frama-c!4232

[Eva] Greatly simplifies Abstractions.mli interface.

See merge request frama-c/frama-c!4224