[xFEM] hopefully simplifying xMesh source
Has we are in the middle of a big change the modify state stuff were appearing in xMesh despite their AOMD nature. To simplify, comments are removed and xinterface::aomd::modifyAllState function is use in replacement of the ugly set of 12 calls to modifyState method. This will certainly disappear in the future Remove comment regarding printMesh/printEntity. A future commit will bring them back alive.