ENH: Added new abaqus sampledSet

Generates sample positions from points specified in a file as Abaqus mesh
points.

Example usage:

    sets
    {
        cone25 // user-specified set name
        {
            type        abaqusMesh;
            file        "abaqusMesh.inp";

            // Optional entries

            // Scale, e.g. mm to m
            scale       0.001;

            // Search distance when the sample point is not located in a cell
            maxDist     0.25;

            ...
        }
    }