Render stats text: show elapsed time for blender internal, hide useless "Single Layer"

at the start, more clearly indicate what the render time of the last frame was, some
other tweaks for consistency.

source/blender/render/extern/include/RE_pipeline.h

@@ -145,6 +145,7 @@ typedef struct RenderStats {
 	int cfra;
 	int totface, totvert, totstrand, tothalo, totlamp, totpart;
 	short curfield, curblur, curpart, partsdone, convertdone, curfsa;
+	bool localview;
 	double starttime, lastframetime;
 	const char *infostr, *statstr;
 	char scene_name[MAX_ID_NAME - 2];