[Scenario] Suppress scroll bars for timeline views

Suppress MCT-provided scroll bars for timeline
views; this facilitates introduction of inner
scroll panel for nasa/MCT-Plugins#114.
[Scenario] Fix horizontal sizing of timelines

Fix horizontal sizing of timeline views
with respect to container. Specifically, size
to fit the containing scrollable viewport iff
the viewport is larger than the preferred
size of the timeline local controls.
[Scenario] Add vertical scroll to timeline area
[Scenario] Don't use scrollpane for nested timelines

Remove ScrollPane (added for nasa/MCT-Plugins#114)
for nested timeline-style views (e.g. Timelines
in a Scenario, Cost Graphs in a Timeline...)
[Scenario] Increase right margin in timelines

Increase right margin in timelines to account for
the space that may be consumed when a scroll bar
appears.
[Scenario] Adjust positioning calculations

Avoid using getWidth() when drawing/positioning
visual elements which need to be time correlated;
the width of a component may be less than the
width of the container which shows tick marks,
due to the possible inclusion of a scroll bar
on the right hand side which pushes over timeline
contents, but not the tick marks in the lower
control area.
Merge pull request #143 from VWoeltjen/mctPlugins114

[Scenario] Scroll vertically in timeline area only