Merge pull request swagger-api#2726 from swagger-api/prepare-release-…

…2.0.0

prepare release 2.0.0

Merge pull request swagger-api#2544 from swagger-api/prepare-rc3

prepare release candidate 2.0.0-rc3

Merge pull request swagger-api#2549 from swagger-api/prepare-release-…

…1.5.17

prepare release 1.5.17

updated version

Merge pull request swagger-api#2258 from swagger-api/release-prepare

updated versions for release