histogram can now be filled in the same for loop as min/max/sum
added OpenCascade STEP and IGES file types, changed file_type to filetype
changed parameter name  file_type to filetype
renamed line_mesh_generator to make_line_mesh
renamed triangle_mesh_generator/triangle_hull_mesh_generator to triangle_make_mesh/triangle_make_hull
renamed tetgen_mesh_generator to tetgen_make_mesh
renamed netgen_csg_mesh_generator/netgen_occ_mesh_generator to netgen_csg_make_mesh/netgen_occ_make_mesh
updated to new algorihm names