index: Adjusted comma placement

With the line break the comma had whitespace in front, which looked
a bit ugly.
index: Don't underline "SkyLines" link

It is already bold, it doesn't have to be underlined.
index: Merged font-weight:bold definitions
index: Adjusted SkyLines tag line

SkyLines is not only used for sharing flights, but also for live tracking.
index: Moved sidebar back to the top