Fixed progress bar bugs

Added "share" action to list context menu, however not functional yet.
Set larger height for title label for list renderer because bottom of
text was being cut off. Need to fix problem downloading tracks to
device, and random empty lists that sometimes occur. Changes to progress
bar: Track length is taken from model data (json) at first and when
entire sound file is downloaded from web, track length is updated with
more accurate value from sound file. This way, progress bar starts
moving right away, and seemed to fix spurratic jumping tracks and crazy
numbers in track progress label.