Corrected evaluation of yound modulus in evaluation of CZM softening function

In the previous version, for CZM equivalence, whenever the softening function H or its derivative was evaluated, an evaluator of the young modulus E was called. This was due to the fact that E can eventually not be homogeneous inside the domain. However, this was rather not optimal, because the constant lambda which appears inside the expression of H is evaluated whenever H is evaluated.

Therefore, the evaluator of E inside the evaluator of H is replaced by a constant double equal to E. This double was added to the CZM parameters (CZM_E), to be read from the damageinfo.dat file. We assume here that we have ony one "TLS model" in the computation domain (E may eventually be non homogeneous in the domain, but we assume that this is only due to stiff non damageable zone for instance).

A drawback is that consistency of CZM_E with the value given by the evaluator of E inside the main.cc must be checked.

Also, some tests to check the conditions on the CZM parameters (see Parilla Gomez (2015) were added.

Fixes #8 (closed).