Hide collection on list if no routes in collection

[Hayden2018]

Currently collections are shown under the collections tab even if no routes are in the collection, making it looks like an layout bug. This commit hide the entire collection if there are no routes in that collection.

[chunlaw]

I have tried it. Would you like to add an image to instruct user how to add route to collection? Otherwise, it will be a blank page for new users, and they likely have no idea what's going on

[Hayden2018]

I think that make sense. For consistency sake all other tabs including "常用" or "Home" should show the same image when having no data? Maybe similar to the one in "車站" ?

[chunlaw]

Yes, go ahead. Suggested to prepare 4 images, each for one combination of language and color theme.

[Hayden2018]

Sure. Will see what i can do.