Gtk2 apidoc TODO's, and a apidoc general todo

["Ross McFarland" <rwmcfa1 neces com>]

the following is the current output of doc_helper.pl

xs/GtkClipboard.xs|386| PPCODE section in Gtk2::Clipboard::wait_for_targets
xs/GtkClipboard.xs|386| ... arg in Gtk2::Clipboard::wait_for_targets
xs/GtkClipboard.xs|386| unknown arg type for ... in
Gtk2::Clipboard::wait_for_targets
xs/PangoTabs.xs|24| ... arg in Gtk2::Pango::TabArray::new
xs/PangoTabs.xs|24| unknown arg type for ... in Gtk2::Pango::TabArray::new
xs/GdkProperty.xs|114| ... arg in Gtk2::Gdk::Window::property_change
xs/GdkProperty.xs|114| unknown arg type for ... in
Gtk2::Gdk::Window::property_change

there were several others that i went through and fixed, but these are pretty
specialized functions and i would prefer that whoever bound them doc'd them.

as for the general todo. we need to come up with a way to add methods to the
list of an object's methods when there's no xsubs for them. my first thought
was to do a trick like the see_also one i did the other day, but the xsubs are
much more complex. i guess who ever is invloved and interest ought to get
togeter on irc at some point and figure something out. the case where this
happens is when a method exists in a pm file rather than xs. i don't think
there are any occurances of this in Gtk2 anymore, but it's a pretty common
thing.

-rm