[E-ACSL] my previous tentative patch did not work. I prefer to have E-ACSL that works than non-regression tests...

[E-ACSL] fixed bug in debug mode
[E-ACSL] add missing headers

[E-ACSL] e_acsl_assert now takes the crashing function in argument

[E-ACSL] prevent runtime errors in annotations (all of them)
[E-ACSL] fixed bug in interpretation of \valid(\at(...))
[E-ACSL] fixed bug in interpretation of locals in blocks involved in memory model

[E-ACSL] fixed bug with array as argument of functions

* fixes bug:
  - fixed bug in quantifications when the bound variable got C type
  - fixed bug with DEV_FLAGS in Makefile.in
* implements new E-ACSL features:
  - invariant as assertion
  - existential quantification \exists over integers
  - equivalence <==>
  - \at as a predicate
  - conditional _ ? _ : _ (for terms and predicates)
  - binary boolean operations over terms
  - mixed assumes and ensures in function contracts
* other new features:
  - better error messages when runtime checks fail 
    (replace e_acsl_fail by e_acsl_assert)
  - remove option -e-acsl-assert
  - add E-ACSL manuals in doc/manuals
  - add files doc/Changelog, INSTALL, README and VERSION
  - new option -e-acsl-version
  - check Frama-C version at configure
  - make src-distrib
  - header 2012

[e-acsl] do not stop anymore when detecting an invalid/unsupported annotation
[e-acsl] tests for invalid quantifications

[e-acsl] universal quantifiers over integers. Not yet finished: work only in some cases
[e-acsl] logic variables (required by univ quantif)

[e-acsl] support of assumes without ensures in stmt contracts
[e-acsl] partial support of function contracts (the same subset than stmt contracts)
[e-acsl] additional test for nested code annotation
[e-acsl] code refactoring: visit.ml splitten into several compilation units

[e-acsl] add guard before divisions and modulos