fixes color handling

plugins/com.minres.scviewer.e4.application/src/com/minres/scviewer/e4/application/Messages.java

@@ -78,6 +78,7 @@ public class Messages extends NLS {
 	public static String signalz;
 	public static String signalx;
 	public static String signalu;
+	public static String signal_change;
 	public static String signal_text;
 	public static String signal_real;
 	public static String signal_nan;

plugins/com.minres.scviewer.e4.application/src/com/minres/scviewer/e4/application/messages.properties

@@ -72,6 +72,7 @@ signal1=Signal Value '1'
 signalz=Signal Value 'Z'
 signalx=Signal Value 'X'
 signalu=Signal Value 'U'
+signal_change=Signal change
 signal_text=Signal text
 signal_real=Signal real Value
 signal_nan=Signal NaN Value