Upgrade js-yaml

Fixes dumping of "yes" and "no" keys, which much be quoted.

See http://juliankniephoff.wordpress.com/2012/09/01/reserved-words-in-yaml-and-translating-booleans-in-rails/

Fixes #2286.
Use correct translation keys
Simplify
Don't automatically tag motorways, etc. as oneway=yes
Fixed chrome selection bug (fixes #2151)
Update translations
1.5.2