fix missing semicolons in various .m files * playaudio.m, accumarray.m, accumdim.m, bicubic.m, narginchk.m, nargoutchk.m, nthargout.m, image.m, pkg.m, colorbar.m, hdl2struct.m, legend.m, plotyy.m, private/__go_draw_axes__.m, private/__print_parse_opts__.m, shrinkfaces.m, pchip.m, polyval.m, rundemos.m: Fix lines with missing semicolons.