Toolbars do not align with edge of plot in fixed-width mode

[abought]

When using fixed-width plots, the plot toolbar is allowed to flow to the edge of the container, but the plot is not. This leads to an awkward display artifact where labels and buttons are not aligned with panels. Panel toolbars are positioned ok; it is only the plot toolbar that looks odd.

This happens with various CSS frameworks (plain HTML, skeleton, bootstrap etc)

Most modern usages of LocusZoom are set to use responsive resize = true, and so this behavior is not widely obvious in most sites. However it is a bit ugly.