Convert C3D8 Hexahedral Elements to C3D20

Automatically convert C3D8 elements to C3D20.

This function is primarily used to convert 8 noded hexahedral elements to 20 noded. It's useful if you are using automatic element meshing software's that do not offer output in C3D20 such as IA-FEMESH.

Input: Node Matrix in standard input file format
[NodeNumber,NodePositionx,NodePositiony,NodePositionz;...]
Element Matrix in standard input file format
[ElementNumber,Node1,Node2,...,Node8;...]

Outputs: Writes 2 separate input files for the new nodes and new elements.
the files can then be loaded after, or you can just add them to
be outputs yourself!

Comments: It should be mentioned that the interior edge nodes are linearly interpolated between corresponding edge-end nodes. There is room for improvement if you first convert the entire element to the isoparametric space before getting the middle point, and then going back. This should only be considered if your elements are badly deformed in the first place.

If the public suggests there is a need through comments, I can add that as well