Allow specifying order for dropdown menu items

[bs2609]

This adds a new optional property ordered for dropdown-type settings, which allows specifying the order the dropdown items should appear in. Currently, all dropdown items are unconditionally sorted alphabetically and it would be good to have a way to override this (somewhat unexpected) behaviour for settings that may have a logical ordering that is non-alphabetical.

With this change, if ordered = true is defined, options will be taken to be an ordered list and passed to setdropdownitems as such. Otherwise, existing behaviour is preserved.

The corresponding wiki page will also need updating to mention the additional ordered key for select type options.

Example usage:

{ name='testing', type='select', label="test setting please ignore", options={'la','li','lu','le','lo'}, ordered=true }