remove unnecessary old docs and rename some dir names
add untranslated 2.1.5 docs
copy translations in common with 2.1.3
copy translations in common with 2.1.3 and translate added part. refs #482
copy translations in common with 2.1.3 and translate added part. refs #484
copy translations in common with 2.1.3 and translate added parts. refs #485
translate added doc. refs #483
remove 2.1.3 docs and bump up latest version to 2.1.5
update download module's version to 2.2.0
modify to redirect to the latest version of each minor releases when requeseted version already removed
bump up the gae application version