Support blank strings in modopts.ini

Use the new "blanks" option with File.iniGetAllObjects().
This means that keys specified in the modopts.ini with no value
will now be represented as blank strings ("") instead of undefined values,
in JS modules.

exec/load/modopts.js

@@ -29,7 +29,7 @@ function get_mod_options(modname, optname, default_optval)
 	if(optname)	// Get a specific option value (optionally, with default value)
 		val = ini_file.iniGetValue(modname, optname, default_optval);
 	else // Get all options
-		val = ini_file.iniGetObject(modname);
+		val = ini_file.iniGetObject(modname, /* lowercase */false, /* blanks: */true);
 	ini_file.close();
 	return val;
 }