add 2.1.1 docs
bump up the version.latest to 2.1.1
copy translations in common with 2.1.0
copy translations in common with 2.1.0. refs #381
copy the translations from 2.1.0. refs #381

all of differences of original docs were just fix of typo
copy translation in common with 2.1.0. refs #382
translate added parts. refs #382
copy translation in common with 2.1.0. refs #383
translate added parts. refs #383
oops, forgoten to translate the added part. refs #382
copy translation in common with 2.1.0. refs #384
translate a added part. refs #384
copy translations in common with 2.1.0. refs #386
translate a added part. refs #386
copy translations in common with 2.1.0. refs #387
translate added parts. refs #387
update the latest package information. refs #407
update logo of companies already using playframework. refs #407
update issue tracker information of top page footer. refs #408
update issue tracker information of get involved page. refs #408