fix for i18n stuff in IE10 and china firefox

[deanhiller]

Added a unit test where in china, the request from firefox browser was resulting in displaying english which can frustrate users there who have zh_cn as their first language. The previous code picked the first lang match in the list in application.conf instead of the first in the list of the browsers request.

[cloudbees-pull-request-builder]

play-1-3-x-pull-requests #144 FAILURE Looks like there's a problem with this pull request

[xael-fry]

Could you create an issue? Could you fix the test Map<String, Header> headers = new HashMap<>(); only compile for 1.7 Just change it to must be fine Map<String, Header> headers = new HashMap<String, Header>();

Other remark, in your test the request want zh_cn, en or en_us. So that means that the user want one of this exact match. I your webiste is in zh_tw, showing this language instead of the requested zh_cn, is not good neither. As all chinese from china (zh_cn : simplifed character) cannot read Traditional characters (zh_tw), so en will maybe better for them. So as for me, I would prefer the previous behaviour.

But your example show some problem in Play, if the request contains "zh_cn,en;q=0.3,en_us;q=0.7" and play has defined en-us and en, play.getLang should return en_us (as we should consider the q value "relative quality factor").