Write Abaqus Hexahedron Filter Enhancements

* Voxels are currently designated as element type C3D8 in the _elems.inp file, which contains 8 integration points and does not use the *Hourglass Stiffness argument within ABAQUS. The hourglass argument is only used for reduced integration C3D8R elements. That being said, it would be useful if this filter had a checkbox like "Use reduced integration elements" to designate *Element, type=C3D8 in _elems.inp if the user actually wants reduced integration elements (and if so, the filter should then ask for the Hourglass Stiffness Value). If the box is unchecked, _elems.inp should specify C3D8 and not include Hourglass Stiffness in the _sects.inp file. Thoughts?

* The only remaining section of an ABAQUS .inp file that is missing now is one that specifies load steps. A filter like this would greatly benefit the modeling community and reduce our need for outside MatLab/python scripts to finish generating what we need for simulations. Is a filter like this in the plan?