add GraphControlsView
add graph controls to moving chart only
add model to GraphControlsView
render graph controls on model change
pass slider's range to its constructor
use the range to replace hardcoded values
set value on model
move slider at chart.redraw
vertical slider
add checkbox to switch auto play
change label when checkbox clicked
stop when when switched to manual
manually set slider value
disable slider in auto
extract morph in a separate function
update chart in manual mode
resume when auto switched back on
Merge branch 'year-slider'