make arrays one dimensional

With more dimensional arrays we have to define the array size. Use
one dimensional arrays to be more flexible.
Additionally this allows to shrink array size for ASCII.

Meter.h

@@ -119,6 +119,9 @@ ListItem* Meter_toListItem(Meter* this, bool moving);
 
 /* ---------- GraphMeterMode ---------- */
 
+#define PIXPERROW_UTF8 4
+#define PIXPERROW_ASCII 2
+
 /* ---------- LEDMeterMode ---------- */
 
 extern MeterMode* Meter_modes[];