Proper support for quoted identifiers in models

[bclement-ocp]

          By the way we probably have a problem with quoted identifiers as well… This is unrelated to this PR however.

Originally posted by @bclement-ocp in #804 (comment)

We do.

$ cat quoted.smt2
(set-logic ALL)
(declare-const |fail))| Int)
(assert (= |fail))| 0))
(check-sat)
(get-model)
$ alt-ergo --frontend dolmen --produce-models quoted.smt2
                                       
; File "quoted.smt2", line 4, characters 1-12: I don't know (0.4269) (1 steps) (goal g_1)

unknown
(
  (define-fun fail)) () Int 0)
)

[bclement-ocp]

Assigning @Halbaroth who said he was interested in tackling this

[Stevendeo]

There are few ways to tackle this issue. If Dolmen does not provide the information that the identifier was defined quoted (which would be IMO the best way to do to precisely match the user input), we can :

• quote all the names in the output (easy, no cost, 100% sound)
• check all names when they are built or printed that they do not contain special characters (not as easy, negligible-but-existent cost, error prone)