update simplified chinese translation

@BillFZhu, @wongsyrone, @tungstwenty, @fenghn888, @jokies
@jpeg729, @pyler, @tonymanou
Merge branch 'upstream' into patch-translate
Merge branch 'upstream' into patch-translate
update simplified chinese translation
Merge pull request #1087 from liudongmiao/patch-translate

Updated simplified Chinese translation