Final Commit (for now)

list of known bugs/not yet implemented feature:
- fullscreen button (custom control didn't show on fullscreen state)
- duration seekBar (sometimes off-duration, because it defined each 1s,
not that precise)
- youtubeplayer api didn't allow overlaying the player with other view
- loading animation on "load more" button click (not yet implemented)
- volume seekbar didn't change on volume change using hardware volume
button
- maybe more.......
- haven't signed the apk