Fix #33 - [Music] Landscape layout

* now player view contains "player-container" and "player-list-container". All original contents goes to former.
* BB changes for headers.
* Use nth-child rather than main-tile/sub-tile
* Most of the changes goes in media query section.
(And because main-tile&sub-tile are removed in .js, both portrait mode and 320x480 doesn't work. We need to re-write rule using :nth-child for 320x480 if we want to uplift to Bugzilla)