[Scenario] Update composite pan/zoom sliders

Update position of composite pan/zoom sliders
when start and end times are changed elsewhere
(e.g. due to panning.)
[Scenario] Add connecting lines above pan/zoom control

Add connecting lines above composite pan/zoom
control in timeline views to visually correlate
the position of those sliders with the time
span shown in tick marks above.
[Scenario] Make edge width of MultiSlider gettable

Provide getter for edge width (pixels not
allocated to the slideable portion of the
component) of Multi-Slider; this will allow
other components (connecting lines) to
align themselves visually.
[Scenario] Align connecting lines

Account for internal positioning of
MultiSlider when drawing connecting lines
to illustrate its relationship to the
visible timescale.
[Scenario] Decrease connector height

Decrease vertical space consumption of lines
which connect multi-slider to tick marks in the
time line view.
[Scenario] Tweak color, position of pan/zoom