Add new function,
In ibex_Affine2Eval.h:
ExprLabel& eval_label(const Function& f, const Affine2Vector& box)
Affine2Domain& eval(const Function& f, const Affine2Vector& box) 

In ibex_Function.h:
void write_arg_af2_domains(const Affine2Vector& box) 
Affine2        eval_affine2 (const Affine2Vector& box) 
Affine2Domain& eval_affine2_affinedomain(const Affine2Vector& box)
Affine2Vector  eval_affine2_vector (const Affine2Vector& affine)
Affine2Matrix  eval_affine2_matrix (const Affine2Vector& box)
correct a bug in Function::eval_affine2
Merge branch 'jordan' of https://github.com/ibex-team/ibex-lib into jordan