Add a dest_profile parameter to gimp_image_convert_type() so a profile can be chosen when converting between RGB and GRAY. Has no GUI yet.
because it confuses gtk-doc and breaks some links. Also change the "Index of new symbols in GIMP 2.x" sections to be what seems to be the modern standard (looked at the GLib and GTK+ docs), and update some other stuff.
This only renames files, no code changes.
