Reducing again the deps of mapping to Trellis, Trellis_Util::mPoint is replaced by  xtensor::xPoint in xmapping.
     xMapping/src/xMapping.h do not include mPoint.h anymore.

    consequences outside xmapping :
    - xCrack/src/SingularCrackMapping.cc : SingularCrackMapping : member bounding box now take xtensor::xpoint as outpout parameter.
    - xFEM/src/xGeomElem.cc : now include "xPoint.h". xGeomElem Member GetBoundingBox corrected to call xmapping's bounding box using xtensor::xPoint.
    - xInterface/AOMD/general/src/xAOMDEntityUtil.h now include xPoint.h.
       function getPoint signature changed to std::vector<xtensor::xPoint> getPoints(const AOMD::mEntity &e).