Merge pull request #204 from krzysiekbarca/master

CLU-220 related
added gent content to screenshots - CLU220 related
Merge branch 'master' of github.com:bitbar/testdroid-api
Merge pull request #207 from krzysiekbarca/master

added getting content from APIScreenshot
screenshot get content fix: json serialization failed so far
Merge pull request #208 from kajdus/master

screenshot get content fix: json serialization failed so far
Merge branch 'master' of github.com:bitbar/testdroid-api into devel