Changes in gmsh_io.C for -Wshadow.

Issue #24.
Changes in gmv_io.C for -Wshadow.

Issue #24.
Changes in gnuplot_io.C for -Wshadow.

Issue #24.
Changes in matlab_io.C for -Wshadow.

Issue #24.
Changes in legacy_xdr_io.C for -Wshadow.

Issue #24.
Changes in medit_io.C for -Wshadow.

Issue #24.
Changes in mesh_communication.C for -Wshadow.

Issue #24.
Changes in mesh_data_tetgen_support.C for -Wshadow.

Issue #24.
Changes in mesh_data.C for -Wshadow.

Issue #24.
Changes in mesh_generation.C for -Wshadow.

Issue #24.
Changes in mesh_modification.C for -Wshadow.

Issue #24.
Changes in mesh_refinement.C for -Wshadow.

Issue #24.
Changes in mesh_smoother_vsmoother.C for -Wshadow.

Issue #24.
Changes in mesh_smoother_laplace.C for -Wshadow.

Issue #24.
Changes in mesh_tetgen_interface.C for -Wshadow.

Issue #24.
Changes in mesh_triangle_holes.C for -Wshadow.

Issue #24.
Changes in off_io.C for -Wshadow.

Issue #24.