Move API reference down one level

Since we only have one API reference, we can drop the clutter/
sub-level, and have all the files under doc/reference.

doc/reference/clutter.types

@@ -0,0 +1,122 @@
+cally_actor_get_type
+cally_clone_get_type
+cally_group_get_type
+cally_rectangle_get_type
+cally_root_get_type
+cally_stage_get_type
+cally_text_get_type
+cally_texture_get_type
+cally_util_get_type
+clutter_action_get_type
+clutter_actor_box_get_type
+clutter_actor_get_type
+clutter_actor_meta_get_type
+clutter_align_constraint_get_type
+clutter_alpha_get_type
+clutter_animatable_get_type
+clutter_animation_get_type
+clutter_animator_get_type
+clutter_animator_key_get_type
+clutter_backend_get_type
+clutter_behaviour_depth_get_type
+clutter_behaviour_ellipse_get_type
+clutter_behaviour_get_type
+clutter_behaviour_opacity_get_type
+clutter_behaviour_path_get_type
+clutter_behaviour_rotate_get_type
+clutter_behaviour_scale_get_type
+clutter_bin_layout_get_type
+clutter_bind_constraint_get_type
+clutter_binding_pool_get_type
+clutter_blur_effect_get_type
+clutter_box_get_type
+clutter_box_layout_get_type
+clutter_brightness_contrast_effect_get_type
+clutter_cairo_texture_get_type
+clutter_canvas_get_type
+clutter_child_meta_get_type
+clutter_click_action_get_type
+clutter_clip_node_get_type
+clutter_clone_get_type
+clutter_color_get_type
+clutter_color_node_get_type
+clutter_colorize_effect_get_type
+clutter_constraint_get_type
+clutter_container_get_type
+clutter_content_get_type
+clutter_deform_effect_get_type
+clutter_desaturate_effect_get_type
+clutter_device_manager_get_type
+clutter_drag_action_get_type
+clutter_drop_action_get_type
+clutter_effect_get_type
+clutter_event_get_type
+clutter_event_sequence_get_type
+clutter_fixed_layout_get_type
+clutter_flow_layout_get_type
+clutter_fog_get_type
+clutter_geometry_get_type
+clutter_gesture_action_get_type
+clutter_glx_texture_pixmap_get_type
+clutter_grid_layout_get_type
+clutter_group_get_type
+clutter_image_get_type
+clutter_input_device_get_type
+clutter_interval_get_type
+clutter_keyframe_transition_get_type
+clutter_knot_get_type
+clutter_layout_manager_get_type
+clutter_layout_meta_get_type
+clutter_list_model_get_type
+clutter_margin_get_type
+clutter_media_get_type
+clutter_model_get_type
+clutter_model_iter_get_type
+clutter_offscreen_effect_get_type
+clutter_page_turn_effect_get_type
+clutter_paint_node_get_type
+clutter_paint_volume_get_type
+clutter_pan_action_get_type
+clutter_param_color_get_type
+clutter_param_fixed_get_type
+clutter_param_units_get_type
+clutter_path_constraint_get_type
+clutter_path_get_type
+clutter_path_node_get_type
+clutter_perspective_get_type
+clutter_pipeline_node_get_type
+clutter_point_get_type
+clutter_property_transition_get_type
+clutter_rect_get_type
+clutter_rectangle_get_type
+clutter_rotate_action_get_type
+clutter_score_get_type
+clutter_script_get_type
+clutter_scriptable_get_type
+clutter_scroll_actor_get_type
+clutter_settings_get_type
+clutter_shader_effect_get_type
+clutter_shader_float_get_type
+clutter_shader_get_type
+clutter_shader_int_get_type
+clutter_shader_matrix_get_type
+clutter_size_get_type
+clutter_snap_constraint_get_type
+clutter_stage_get_type
+clutter_stage_manager_get_type
+clutter_state_get_type
+clutter_state_key_get_type
+clutter_swipe_action_get_type
+clutter_table_layout_get_type
+clutter_tap_action_get_type
+clutter_text_buffer_get_type
+clutter_text_get_type
+clutter_text_node_get_type
+clutter_texture_get_type
+clutter_texture_node_get_type
+clutter_timeline_get_type
+clutter_transition_get_type
+clutter_transition_group_get_type
+clutter_units_get_type
+clutter_vertex_get_type
+clutter_zoom_action_get_type