update copyright year
Update number-format.js

Corrects bug where currency suffix was overwritten by SI-prefix formatting.
Updated test/locale for suffix bug
Merge pull request #1721 from gdi2290/patch-1

update copyright year
Merge branch 'master' of github.com:jbblanchet/d3 into fix-prefix
Tweak comment. Add another test.
Merge branch 'fix-prefix'