matrix: Adds matrix_copy and _free functions

As a pre-requisite for being able to register a boxed GType for
CoglMatrix (enabling us to define gobject properties that accept a
CoglMatrix) this adds cogl_matrix_copy and _free functions.

cogl/cogl-matrix.c

@@ -353,6 +353,21 @@ cogl_matrix_equal (gconstpointer v1, gconstpointer v2)
     return FALSE;
 }
 
+CoglMatrix *
+cogl_matrix_copy (const CoglMatrix *matrix)
+{
+  if (G_LIKELY (matrix))
+    return g_slice_dup (CoglMatrix, matrix);
+
+  return NULL;
+}
+
+void
+cogl_matrix_free (CoglMatrix *matrix)
+{
+  g_slice_free (CoglMatrix, matrix);
+}
+
 const float *
 cogl_matrix_get_array (const CoglMatrix *matrix)
 {

cogl/cogl-matrix.h

@@ -292,6 +292,33 @@ cogl_matrix_get_array (const CoglMatrix *matrix);
 gboolean
 cogl_matrix_equal (gconstpointer v1, gconstpointer v2);
 
+/**
+ * cogl_matrix_copy:
+ * @matrix: A 4x4 transformation matrix you want to copy
+ *
+ * Allocates a new #CoglMatrix on the heap and initializes it with
+ * the same values as @matrix.
+ *
+ * Returns: A newly allocated #CoglMatrix which should be freed using
+ * cogl_matrix_free()
+ *
+ * Since: 1.6
+ */
+CoglMatrix *
+cogl_matrix_copy (const CoglMatrix *matrix);
+
+/**
+ * cogl_matrix_free:
+ * @matrix: A 4x4 transformation matrix you want to free
+ *
+ * Frees a #CoglMatrix that was previously allocated via a call to
+ * cogl_matrix_copy().
+ *
+ * Since: 1.6
+ */
+void
+cogl_matrix_free (CoglMatrix *matrix);
+
 /**
  * cogl_matrix_get_inverse:
  * @matrix: A 4x4 transformation matrix