Separate CSS styles for reference point links to points with zero and nonzero context counts.
Scale reference point link lines proportional to the fraction of events of the source point accounted for.
Bring reference point marker groups to front on hover to make link lines go on top of any other markers.
Enabled reference point link scaling by default, with maximum width of 8.
Merge pull request #107 from sfu-natlang/linkedreferencepoints

More improvements to reference point links on the frontend