Add "omit implicit acc operand" feature

By default, implicit acc operands are shown, e.g. "LSR A" rather
than just "LSR".  I like showing operands for instructions that
have multiple address modes.

Not everyone agrees, so now it's a setting.  They're shown by default,
but enabling the option will strip them on-screen, in generated
assembly, and in the instruction chart.

They are always omitted for ACME output, which doesn't allow them.

(issue #162)

SourceGen/MainController.cs

@@ -508,6 +508,8 @@ namespace SourceGen {
                 settings.GetString(AppSettings.FMT_LOCAL_VARIABLE_PREFIX, string.Empty);
             mFormatterConfig.CommaSeparatedDense =
                 settings.GetBool(AppSettings.FMT_COMMA_SEP_BULK_DATA, true);
+            mFormatterConfig.SuppressImpliedAcc =
+                settings.GetBool(AppSettings.SRCGEN_OMIT_IMPLIED_ACC_OPERAND, false);
             mFormatterConfig.DebugLongComments = DebugLongComments;
 
             string chrDelCereal = settings.GetString(AppSettings.FMT_CHAR_DELIM, null);