Oxz manager extras

Hotkeys for advanced features

* 'f' => filter OXZ list
* 'i' => view OXZ info
* 'x' => extract OXZ to be a disabled OXP in your AddOns folder

Now also reminds users to refresh the list when starting the OXZ manager.

Needs a slight change to the manifest API making before this can be merged into master so that extended descriptions are not sent to Oolite 1.80