[E-ACSL] fix some headers and update TODO-list

[E-ACSL] improve user manual a bit
[E-ACSL] add missing test

[E-ACSL] add missing test

[E-ACSL] improve ACSL contracts of its libraries
[E-ACSL] no more unknow locations in translation of quantifications

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

[E-ACSL] code of e_acsl_assert put in e_acsl.c (no more in e_acsl.h)

[E-ACSL] convert postcondition even in presence of untranslated assigns clause
[E-ACSL] fix bug when the translation of a predicate containing \at is abruptely stopped because of a not-yet-implemented construct (the generated code contained undeclared __e_acsl_at variables)

[E-ACSL] fixed bug when translating left-values with complex types (related to bug #1326)
[E-ACSL] fixed issue #1329: the 'requires' clause is now interpreted even if an other part of the precondition cannot be evaluated.

[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 #1307 (typing crash in presence of reals)
[E-ACSL] fixed bug in the pre-analysis on function call
[E-ACSL] fixed bug with non-integer operators with a GMP operand