Add the select boxes for various map tile and search providers, in ad…

[xuxinhang]

…dition to UI improvement.

[xuxinhang]

Hi.

The default tile and search provider is blocked by my ISP, so I studied and managed to change the two providers. Supposing other users like me might also face this problem, I add the select boxes allowing to choose among various provides.

Besides, UI is also updated for a tidier look.