Improve preferences options

[scottmc]

Preferences should be expanded to include an option for selecting the output directory.

[scottmc]

You can current edit the output directory text on the encode line. But a better solution would be a directory select tool.

Selecting the other options might be put into a list box and allow the user to drag them into the order they would like them to be, and maybe hide the encode line from the user. the list should allow the user to sort them as they wish, and maybe uncheck ones they don't want.

[scottmc]

See comments at end of #24 discussion about how the preferences selection might work.