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/set/setdiff.m	Mon Feb 23 16:42:25 2015 +0000
+++ b/scripts/set/setdiff.m	Mon Feb 23 14:54:39 2015 -0800
@@ -115,7 +115,7 @@
 %! assert (c, [5]);
 %! assert (c, a(ia));
 
-%% Test output orientation compatibility (bug #42577)
+## Test output orientation compatibility (bug #42577)
 %!assert (setdiff ([1:5], 2), [1,3,4,5])
 %!assert (setdiff ([1:5]', 2), [1;3;4;5])
 %!assert (setdiff ([1:5], [2:3]), [1,4,5])