Add PNG connection type and Freetype 2 font rendering to glcd driver. The PNG

image writer is for debugging only. The Freetype font renderer still misses
some features (e.g. big numbers, character encoding, non-standard cell size).

server/drivers/glcd-render.h

@@ -0,0 +1,13 @@
+#ifndef GLCD_RENDER_H
+#define GLCD_RENDER_H
+
+int glcd_render_init(Driver *drvthis);
+void glcd_render_close(Driver *drvthis);
+void glcd_render_char(Driver *drvthis, int x, int y, unsigned char c);
+int glcd_render_icon(Driver *drvthis, int x, int y, int icon);
+
+#ifdef HAVE_FT2
+void glcd_render_char_unicode(Driver *drvthis, int x, int y, int c);
+#endif
+
+#endif