viewmodelfx improvements

[Polarhigh]

1. Add functions to get current fx values

native ncl_viewmodelfx_get_renderfx(id);
native ncl_viewmodelfx_get_renderskin(id);
native ncl_viewmodelfx_get_renderbody(id);
// etc...

2. Add some stock functions

stock ncl_viewmodelfx_render(id, renderfx = kRenderFxNone, rendercolor[3] = { 0, 0, 0 }, rendermode = kRenderNormal, renderamt = 0)
{
    ncl_viewmodelfx_begin(id);
    ncl_write_renderfx(renderfx);
    ncl_write_rendercolor(rendercolor[0], rendercolor[1], rendercolor[2]);
    ncl_write_rendermode(rendermode);
    ncl_write_renderamt(renderamt);
    ncl_viewmodelfx_end();
}

stock ncl_viewmodelfx_skin(id, renderskin = 0)
{
    ncl_viewmodelfx_begin(id);
    ncl_write_renderskin(renderskin);
    ncl_viewmodelfx_end();
}

stock ncl_viewmodelfx_body(id, renderbody = 0)
{
    ncl_viewmodelfx_begin(id);
    ncl_write_renderbody(renderbody);
    ncl_viewmodelfx_end();
}

stock ncl_restore_viewmodelfx(id)
{
    ncl_viewmodelfx_begin(id);
    ncl_write_renderfx(kRenderFxNone);
    ncl_write_rendercolor(0, 0, 0);
    ncl_write_rendermode(kRenderNormal);
    ncl_write_renderamt(0);
    ncl_write_renderskin(0);
    ncl_write_renderbody(0);
    ncl_viewmodelfx_end();
}

3. Add automatic support for spectators, so that when observing a player to whom effects have been applied, the observer will also be applied to those effects. This feature should be optional.
4. Add a feature to set hooks on viewmodelfx.