Revert "Add type checking to positional Gtk.Box and Gtk.Window ctor arguments"

This reverts commit 7193f0509a0ed7da7c810daa6733e34a22db3180.
tests: Use explicit keywords args when calling initializers

Replace all usage of GObject creation that relies on positional
arguments from overrides. Positional initializer args will be
deprecated, updating the tests as a first pass proves backwards
and forwards compatibility of the deprecation.

https://bugzilla.gnome.org/show_bug.cgi?id=705810
Add deprecation warnings and cleanup class initializer overrides

Print deprecation warnings for calls to class initializers which
don't explicitly specify keywords. Print deprecation warning
for overrides that have renamed keywords (Gtk.Table.rows should
be n_rows). Additionally deprecate non-standard defaults with
initializers (Gtk.SizeGroup.mode defaults to HORIZONTAL in GTK+
and VERTICAL in PyGI).
Remove AboutDialog override because it doesn't do anything.

https://bugzilla.gnome.org/show_bug.cgi?id=705810
Cleanup overzealous new and init implementations

Remove PyGObject initializer code attempting to set properties on
GObjects that have already been created. There were a number of
overridden __new__ and __init__ methods that stripped away
arguments before calling the base class to work around attempted
property sets and argument count errors (fixing the symptom not
the problem).
Use Gtk.ListStore/TreeStore.new with __new__ override instead
of __init__ with set_column_types.

https://bugzilla.gnome.org/show_bug.cgi?id=705810
Deprecate Gdk.Cursor constructor dispatching

Give deprecation warning for the overridden __new__ method on
Gdk.Cursor when more than one argument is used. Recommend using
Gdk.Cursor.new_for_display, new_from_pixbuf, and new_from_pixmap
instead.

https://bugzilla.gnome.org/show_bug.cgi?id=705810