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/gui/private/__uigetdir_fltk__.m
+++ b/scripts/gui/private/__uigetdir_fltk__.m
@@ -29,7 +29,8 @@
     error ("uigetdir: fltk graphics toolkit required");
   endif
 
-  dirname = __fltk_uigetfile__ ("", dialog_title, start_path, [240, 120], "dir");
+  dirname = __fltk_uigetfile__ ("", dialog_title,
+                                start_path, [240, 120], "dir");
 
 endfunction