Cleanup color button

Cleanup color button

* hildon-widgets/hildon-color-button.c:
        - removed unused #include
        - removed unused gettext macro

        (COLOR_FIELD_WIDTH) : renamed to COLOR_FILLED_WIDTH
        (COLOR_FIELD_HEIGHT): renamed to COLOR_FILLED_HEIGHT
        + value updated to match specifications

        (struct _HildonColorButtonPrivate):
        removed 'drawing_area' and 'pixbuf' members (unused)

        (hildon_color_button_init):
        use drawing_area directly, update COLOR_FILLED_ macro names

        (hildon_color_button_unrealize): new function.
        (hildon_color_button_class_init): register unrealize function
        (hildon_color_button_finalize): free allocated GC in unrealize
        handler instead of in finalize.

        (hildon_color_button_recolor_pixbuf): removed. (use
        gdk_draw_rectangle() instead)
        (hildon_color_button_draw_pixbuf_borders): likewise

        (hildon_color_field_expose_event): use gdk_draw_rectangle() to
        draw the button
        (hildon_color_button_set_property): queue the drawing - instead of
        calling recolor_pixbuf

        (hildon_color_button_clicked): renamed variable 'csd' to 'cs_dialog'