Make use of the axes "ticklabelinterpreter" property (bug #45438) * plot.txi: add an anchor pointing to usage of interpreter property * genpropdoc.m: document axes "ticklabelinterpreter" property and text "interpreter" property * gl-render.h: new private attribute "interpreter" that stores the interperter to be used in text_to_pixels * gl-render.h (set_interpreter): new protected virtual method to set "interpreter" * gl-render.cc (opengl_renderer::draw_axes): set interpreter before rendering tick labels * gl-render.cc (opengl_renderer::text_to_pixels): make use of interpreter attribute * graphics.cc (axes::properties::set_defaults): initialize "ticklabelinterpreter" instead of unused "interpreter" * graphics.in.h (axes::properties): fix doubly defined defaults for "ticklabelinterpreter" and "interpreter" properties

--- a/libinterp/corefcn/gl-render.cc	Thu Jun 25 08:32:21 2015 -0400
+++ b/libinterp/corefcn/gl-render.cc	Tue Jun 23 22:21:50 2015 +0200
@@ -1475,6 +1475,7 @@
   draw_axes_boxes (props);
 
   set_font (props);
+  set_interpreter (props.get_ticklabelinterpreter ());
 
   draw_axes_x_grid (props);
   draw_axes_y_grid (props);
@@ -3229,7 +3230,7 @@
 {
 #if HAVE_FREETYPE
   text_renderer.text_to_pixels (txt, pixels, bbox,
-                                halign, valign, rotation, "none");
+                                halign, valign, rotation, interpreter);
 #endif
 }