Some Android devices does not report the subcode in the language code.

Example:

Mozilla/5.0 (Linux; U; Android 4.1.1; en-; HTC Butterfly Build/JRO03C)
AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30
add test case
Merge pull request #281 from josephsu/master

Some Android devices does not report the subcode in the language code.