Stats - chart 3 rects were below background bands

The rects in chart 3 were positioned below the 0.05 opacity bands and
hence appeared lighter than should be.
fixed band x position
Merge remote-tracking branch 'upstream/master'
Remove 'Top Issue' label from .js

https://bugzilla.mozilla.org/show_bug.cgi?id=1001286
Merge pull request #125 from almossawi/master

Stats chart 3 cleanup, Maps 'Top Issue' label made available to l10n