maint: Clean up m-files to follow Octave coding conventions. Try to trim long lines to < 80 chars. Use '##' for single line comments. Use '(...)' around tests for if/elseif/switch/while. Abut cell indexing operator '{' next to variable. Abut array indexing operator '(' next to variable. Use space between negation operator '!' and following expression. Use two newlines between endfunction and start of %!test or %!demo code. Remove unnecessary parens grouping between short-circuit operators. Remove stray extra spaces (typos) between variables and assignment operators. Remove stray extra spaces from ends of lines.

--- a/scripts/signal/arch_rnd.m
+++ b/scripts/signal/arch_rnd.m
@@ -71,11 +71,11 @@
     b  = [b, 0];
     lb = lb + 1;
   endif
-  m  = max ([la, lb]);
+  m = max ([la, lb]);
 
-  e  = zeros (t, 1);
-  h  = zeros (t, 1);
-  y  = zeros (t, 1);
+  e = zeros (t, 1);
+  h = zeros (t, 1);
+  y = zeros (t, 1);
 
   h(1) = a(1);
   e(1) = sqrt (h(1)) * randn;