Preparing for addressing #361. Change-Id: I4b2e834948e681bc790efc61b63a24d44f70015d
Two-character ISO-639 code in --default_language was ignored due to a bug in language code matching as the language code in stream is always converted to 3-character code. Fixes #371. Change-Id: I8618938af583a417446636ff9efe1c72ce822c33