2006-04-14  Thomas Thurman   <thomas@thurman.org.uk>

        Add a tabbing function, bound to alt-f6 by default, to cycle
        through the windows of the current application. Fixes #164831.

        * src/common.h: two new MetaGrabOpts values for group switching
        * src/display.c (ping_data_free, meta_display_in_grab_op,
        IN_TAB_CHAIN): adapt to new MetaGrabOpts
        * src/display.h: new enum value for MetaTabList for group switching
        * src/keybindings.c (meta_display_process_key_event):
        adapt to new MetaGrabOpts
        (process_tab_grab): adapt to new MetaGrabOpts, and use switch
        statement for cancelling instead of if statement
        * src/metacity.schemas.in: new keybindings
        * src/prefs.c, src/prefs.h: handle new keybindings
        * src/window.h: define META_WINDOW_IN_GROUP_TAB_CHAIN macro