[Android] Improve fast scroller

[Geoffrey Métais]

vlc-android | branch: master | Geoffrey Métais <geoffrey.metais at gmail.com> | Tue Aug  8 16:15:37 2017 +0200| [c5060198ca507cbd1903b09b584d28fc39076234] | committer: Geoffrey Métais

Improve fast scroller

> https://code.videolan.org/videolan/vlc-android/commit/c5060198ca507cbd1903b09b584d28fc39076234
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 .../org/videolan/vlc/gui/view/FastScroller.java    | 107 +++++++++++----------
 1 file changed, 58 insertions(+), 49 deletions(-)

Diff:   https://code.videolan.org/videolan/vlc-android/commit/c5060198ca507cbd1903b09b584d28fc39076234