FaceMaps: add select flag

For use by manipulators since they don't have their own persistent data
in the blend file.

source/blender/makesdna/DNA_object_types.h

@@ -70,6 +70,8 @@ typedef struct bDeformGroup {
 typedef struct bFaceMap {
 	struct bFaceMap *next, *prev;
 	char name[64];  /* MAX_VGROUP_NAME */
+	char flag;
+	char pad[7];
 } bFaceMap;
 
 /* Object Runtime display data */

source/blender/makesrna/intern/rna_object.c

@@ -1778,6 +1778,11 @@ static void rna_def_face_map(BlenderRNA *brna)
 	/* update data because modifiers may use [#24761] */
 	RNA_def_property_update(prop, NC_GEOM | ND_DATA | NA_RENAME, "rna_Object_internal_update_data");
 	
+	prop = RNA_def_property(srna, "select", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", SELECT);
+	RNA_def_property_ui_text(prop, "Select", "Face-map selection state (for tools to use)");
+	/* important not to use a notifier here, creates a feedback loop! */
+
 	prop = RNA_def_property(srna, "index", PROP_INT, PROP_UNSIGNED);
 	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
 	RNA_def_property_int_funcs(prop, "rna_FaceMap_index_get", NULL, NULL);