Bunch of independent changes (ouch)

API additions:

	hb_segment_properties_t
	HB_SEGMENT_PROPERTIES_DEFAULT
	hb_segment_properties_equal()
	hb_segment_properties_hash()

	hb_buffer_set_segment_properties()
	hb_buffer_get_segment_properties()

	hb_ot_layout_glyph_class_t

	hb_shape_plan_t
	hb_shape_plan_create()
	hb_shape_plan_create_cached()
	hb_shape_plan_get_empty()
	hb_shape_plan_reference()
	hb_shape_plan_destroy()
	hb_shape_plan_set_user_data()
	hb_shape_plan_get_user_data()
	hb_shape_plan_execute()

	hb_ot_shape_plan_collect_lookups()

API changes:

	Rename hb_ot_layout_feature_get_lookup_indexes() to
	hb_ot_layout_feature_get_lookups().

New header file:

	hb-shape-plan.h

And a bunch of prototyped but not implemented stuff.  Coming soon.
(Tests fail because of the prototypes right now.)

src/hb-buffer.h

diff --git a/src/hb-buffer.h b/src/hb-buffer.h
index cd574c3..255f005 100644
--- a/src/hb-buffer.h
+++ b/src/hb-buffer.h
@@ -41,8 +41,6 @@
 HB_BEGIN_DECLS
 
 
-typedef struct hb_buffer_t hb_buffer_t;
-
 typedef struct hb_glyph_info_t {
   hb_codepoint_t codepoint;
   hb_mask_t      mask;
@@ -64,6 +62,36 @@
 } hb_glyph_position_t;
 
 
+typedef struct hb_segment_properties_t {
+  hb_direction_t  direction;
+  hb_script_t     script;
+  hb_language_t   language;
+  /*< private >*/
+  void           *reserved1;
+  void           *reserved2;
+} hb_segment_properties_t;
+
+#define HB_SEGMENT_PROPERTIES_DEFAULT {HB_DIRECTION_INVALID, \
+				       HB_SCRIPT_INVALID, \
+				       HB_LANGUAGE_INVALID, \
+				       NULL, \
+				       NULL}
+
+hb_bool_t
+hb_segment_properties_equal (const hb_segment_properties_t *a,
+			     const hb_segment_properties_t *b);
+
+unsigned int
+hb_segment_properties_hash (const hb_segment_properties_t *p);
+
+
+
+/*
+ * hb_buffer_t
+ */
+
+typedef struct hb_buffer_t hb_buffer_t;
+
 hb_buffer_t *
 hb_buffer_create (void);
 
@@ -127,9 +155,21 @@
 hb_buffer_set_language (hb_buffer_t   *buffer,
 			hb_language_t  language);
 
+
 hb_language_t
 hb_buffer_get_language (hb_buffer_t *buffer);
 
+void
+hb_buffer_set_segment_properties (hb_buffer_t *buffer,
+				  const hb_segment_properties_t *props);
+
+void
+hb_buffer_get_segment_properties (hb_buffer_t *buffer,
+				  hb_segment_properties_t *props);
+
+void
+hb_buffer_guess_properties (hb_buffer_t *buffer);
+
 
 typedef enum {
   HB_BUFFER_FLAGS_DEFAULT			= 0x00000000,
@@ -171,9 +211,6 @@
 void
 hb_buffer_reverse_clusters (hb_buffer_t *buffer);
 
-void
-hb_buffer_guess_properties (hb_buffer_t *buffer);
-
 
 /* Filling the buffer in */